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X 7^ 



PURE FOODS 

THEIR ADULTERATION, NUTRITIVE 
VALUE, AND COST 



BY 

JOHN C. OLSEN, A.M., Ph.D. 

PROFESSOR OF ANALYTICAL CHEMISTRY AT THE rOLYTEOHNIC INSTITUTE 

OF BROOKLYN, NEW YORK. AUTHOR OF "QUANTITATI YE CHEMICAL 

ANALYSIS." EDITOR OF VAN NOSTRAND's 

"CHEMICAL ANNUAL," ETC. 



GINN AND COMPANY 

BOSTON • NEW YORK • CHICAGO • LONDON 



-^^^ 



ENTERED AT STATIONERS' HALL 



COPYRIGHT, 1911, BY 
JOHN C. OLSEN 



ALL RIGHTS RESERVED 
811.8 






CIic satbenaeum ^rtiH 

GINN AND COMPANY • PRO- 
PRIETORS • BOSTON • U.S.A. 



OlA2i)^42d 



PREFACE 

This volume is the outgrowth of a series of public 
lectures on foods, which have been given by the author for 
a number of years. The interest shown by audiences of 
widely different character, as well as frequent requests for 
the substance of the lectures in printed form, has led to 
their publication. The experimental illustrations which 
accompanied the lectures are given in the form of a series 
of experiments at the end of each chapter. Some of these 
experiments are so simple that they may be carried out with 
ordmary household utensils, others require a few chemicals 
and simple apparatus which may be purchased at any drug 
store. Many of them require a fairly well-equipped chem- 
ical laboratory, while others have been included which can 
be performed only by those who have considerable chemical 
training and facilities at their command. Most of the descrip- 
tive matter can be understood by the average intelligent 
reader, although even here a knowledge of chemistry will 
enable the reader to comprehend the subject much more 
fully. 

It is the hope of the author that this volume Avill be of 
some service to the very important class of teachers and 
students who are studying the chemistry of foods in the 
classroom and laboratory. It is hoped that the subject has 
been presented in such a manner as to stimulate the interest 
of such classes, and that domestic-science teachers will be 
able to explain and expand the necessarily brief expressions 



iv PUEE FOODS 

of the text, as well as perform such experiments as are be- 
yond the ability of the student. The author also hopes that 
the volume will be of service to the growing class of intelli- 
gent men and women who desire to obtain some knowledge 
of the composition and function of the foods which they 
prepare, sell, or consume. 

Of the great need of a wider and fuller knowledge of 
the nature and functions of the food which is of such vital 
necessity to us, the author has the keenest realization. In 
an age when intelligence and knowledge are recognized as 
essential to the most efficient performance of even very 
simple tasks, it is surprising that most of us eat what we 
like, with ver}^ little thought of the ultimate result. 
y The steel for our bridges and buildings is bought and 
sold on the chemist's certificate of its composition to the 
thousandths of per cent. Foods are manufactured and sold 
on flavor and appearance, utterly regardless of composition 
or food value. The coal for our engines must be tested and 
analyzed, but the far more precious luiman organism is loaded 
with a heterogeneous mixture of fuel of unknown composi- 
tion. We should not be surprised at low efficiency, inability 
to Avork, sickness, even the premature death of an organism 
which is given so little intelligent care. When an intelligent, 
well-informed public demands analyzed, tested foods, they 
will be better served by the food producer, manufacturer, 
and salesman ; and if such food is consumed in tlie physio- 
logically proper quantity and variety, there will be far less 
inefficiency, sickness, and mortality. 

The author does not claim originality for any appreciable 
portion of this volume. For most of the general facts and 
ideas presented he is indebted to the large army of mu- 
nicipal, state, and national pure-food workers, who have 
accumulated so much valuable information on this subject. 



PREFACE V 

The coming generations will reap large harvests of comfort 
and well-being from their quiet but effective work. 

The author wishes to express his indebtedness to many 
of these workers whom it has been his good fortune to know 
personally, and also to many others whom he knows only 
through their publications. Statements made with reference 
to the actual conditions of our food supply are generally 
based, at least in part, on the author's tests of foods in the 
course of his consulting practice as a chemist, and on the 
results of investigations carried out to ascertain the com- 
position of the foods on the market. He need hardly say 
that this volume was not written to meet the needs of the 
technical chemist. 

The autlior takes great pleasure in expressing his obliga- 
tion to Mr. Albert E. Seeker, of the United States Depart- 
ment of Agriculture, for reading the entire manuscript and 
making many valuable suggestions. He is also under obliga- 
tions to Mr. H. C. Humphrey of the Corn Products Refin- 
ing Company for reading the chapters on Carbohydrates 

and Candy. 

J. C. OLSEN 
Brooklyn, New Yokk 



CONTENTS 

CHAPTER PAGE 

I. What is Food? 1 

II. What is Pure Food? 18 

III. Standard Rations and the Cost of Food . 23 

IV. Milk 33 

V. Bacteria in Milk 43 

VI. Fats and Oils 60 

VII. Butter and its Substitutes 71 

VIII. Meats 78 

IX. Carbohydrates 88 

X. Candies 101 

XI. Aniline Dyes and Other Food Colors . . 122 

XIL Preservation of Foods 127 

XIII. Fruits, Jams, and Jellies 141 

XIV. Fresh and Canned Vegetables 155 

XV. Bread and the Cereals 159 

XVI. Leavening Agents 165 

XVII. Spices and Condimental Foods 172 

XVIII. Flavoring Extracts 180 

Appendix ..... 189 

Index 199 

vii 



PUllE FOODS 

CHAPTER I 

WHAT IS FOOD? 

The animal instinct known as appetite has for ages 
answered this question. As man deveh)pe(-l intelhgence he 
learned to avoid eating certain plants or animals which 
produced illness or death, even though they tasted good. 
Still more slowly he acquired crude and often erroneous 
notions of the nutritive value of the wliolesome foods. 
Very little progress has been made until recently in the 
attempt to regulate the amount and proportion of the vari- 
ous foods consumed. Most civilized nations have gener- 
ally overcome the dietary methods by which primitive 
races have alternated between gluttonous indulgence when 
food was plenty and starvation and want at other times. 
Only the very wonderful ability of the human system to 
adapt itself to great extremes in the kind and amount of 
food consumed has enabled man to retain his viffor while 

o 

eating as a savage. The unsanitary condition of the food 
supply has resulted in the introduction into the human 
system of innumerable disease bacteria. Under these con- 
ditions the sacrifice of life has been appalling, especially 
among the immature, aged, and sick. 

Composition of foods. Rapid strides have recently been 
made toward attaining a scientific answer to the question 
as to what constitutes food. The chemist has analyzed the 



2 PURE FOODS 

various organs of the human system and discovered that 
they are in the main composed of but four chemical ele- 
ments ; namely, carbon, hydrogen, oxygen, and nitrogen. 
Substances composed mainly of these four elements are 
called organic matter. The bones and teeth consist largely 
of calcium, phosphorus, silicon, and oxygen, while the 
blood contains considerable quantities of iron and common 
salt, which is a compound of sodium and chlorine. These 
chemical elements as a group are called mineral matter. As 
compounds of these elements are constantly , leaving the 
body, it is evident that to maintain the body weight these 
elements must constitute the bulk of our food, which must 
also be composed of such compounds of these elements as 
can be readily digested and assimilated. There are four 
large classes of chemical compounds which have been found 
to meet these requirements and to constitute the bulk of 
our foods ; namely, carbohydrates, fats, protein, and 
mineral matter. 

Carbohydrates are composed of carbon, hydrogen, and 
oxygen. This class may be subdivided into cellulose, 
starch, and sugar. Cellulose is a very insoluble substance, 
and is the main constituent of wood and vegetable fibers, 
such as cotton and linen. It is not suitable for food on 
account of its insolubility. The starches are also very in- 
soluble compounds. They constitute a large part of most 
seeds and grains. When the grain sprouts, the starch is 
rendered soluble so that it can be dissolved by the sap and 
nourish the growing plant. If the grain is eaten by man, a 
similar transformation takes place during digestion, render- 
ing it possible for the soluble carbohydrate produced to 
dissolve m the blood, which carries it to all parts of the 
system. As cellulose cannot be rendered soluble in this 
manner, it is not suitable for food. 



WHAT IS FOOD? 3 

Sugars. When starch is rendered sokible it passes sooner 
or later into some form of sugar. About two hundred differ- 
ent sugars have been discovered by chemists. Only a few of 
these are present in any large quantity in ordinary foods. 
Cane sugar is the most common of these and is most highly 
prized as a food on account of its sweet taste. It is ex- 
tracted in large quantities from the juice of the sugar cane, 
sugar beet, and maple tree. When starch is rendered solu- 
ble it passes into other sugars which are less sweet, ^such as 
dextrose and maltose. They are fully as nourishing as 
cane sugar and pass into the blood more quickly because 
cane sugar must first be broken up into two simpler sugars 
called dextrose and levulose. 

Solubility of the carbohydrates. The chief difference, 
therefore, between these three classes of carbohydrates is 
found m their solubility. This property is of fundamental 
importance in a food. The body cannot be nourished by 
cellulose because the juices of the body cannot dissolve it. 
Starch can be rendered soluble and can therefore, after 
digestion, nourish the body, while the sugars are almost 
mstantly taken into the circulation, givmg immediate re- 
lief from exhaustion. These three classes of carbohydrates 
contain the same three chemical elements in almost exactly 
the same proportion (carbon, 44.4 per cent; hydrogen, 6.2 
per cent; and oxygen, 49.4 per cent). The same chemical 
formula [(CgHj^Og)"^] is used to represent cellulose, starch, 
and dextrin, which indicates that the chemical elements are 
present in the same proportion (C represents carbon, H 
hydrogen, and O oxygen). The formula for dextrose (grape 
sugar) and levulose is CgHjgOg. This formula differs from 
that of starch by H2O. As H2O is also the formula for 
water, the transformation of starch into dextrose consists 
in the addition of water, and has therefore been called 



4 PURE FOODS 

hydrolysis and may be represented l)y the following chemical 
equation: C^U,,0, + U,0 = C,U,fi,. 

Cane sugar, as well as maltose, is represented by the for- 
mula C12H22O11, and also differs in composition from starch 
by the elements of water, as is seen from the following 
equation : 5 CeH.^O^ + H,0 = C,,lU.fin- 

The fats and oils constitute another of the four large 
classes of foods. These substances are also composed of 
tlie three elements, carbon (about 76.5 per cent), hydrogen 
(about 11.9 per cent), and oxygen (about 11.5 per cent). 
They differ from the carbohydrates in that they contain a 
mucli smaller proportion of oxygen. They are also more 
complex in structure, being composed of glycerin combined 
with fatty acids. When fats become rancid these acids are 
liberated, giving disagreeable odors and tastes. ^ During the 
process of digestion the glycerin is separated from the fatty 
acids. After absorption by the blood these constituents 
are ao^ain united to form the cliaracteristic fats of the 
human system. A small portion of the fat is divided into 
very minute globules which will remain suspended in the 
digestive fluids, producing a liquid similar to milk. The 
animal fats are so similar to each other and to vegetable 
fats that the lard from hogs fed on cottonseed meal will 
give a test for cottonseed oil, indicating that at least a 
portion of this oil has been deposited unchanged in the 
tissues of the animal. 

The proteins constitute the third large class of foods. 
They contain the same three elements as the two preceding 

1 The presence of free acid alone does not constitute rancidity (some acid oils 
not being rancid), but a rancid condition is the result of complex changes 
effected by the action of light and air on oils, causing at the same time the for- 
mation of free acid, so that all rancid oils are acid, l)utnot all acid oils are rancid. 



WHAT IS FOOD ? 5 

classes, but iii addition contain considerable quantities of 
nitrogen (about 16 per cent) as well as small quantities of 
sulphur and phosphorus. Examples of this class of foods 
are the lean portions of meat, the white of eggs, and the 
gluten of wheat. The proteins are of importance in the 
human diet almost solely on account of their content of 
nitrogen. As the living cells of the body cannot be built 
up or nourished on any other food but proteins, it is evident 
that this class of foods is of vital necessity to the liuman 
system. Fats and carbohydrates can, to a certain extent, 
replace each other in the human diet, but neither of these 
can replace protein matter ; neither can the human system 
assimilate nitrogen in any other form than protein. Most 
proteins are readily dissolved by the gastric juice of the 
stomach and the digestive fluids of the intestines. During 
this process the proteins are broken down into a simpler 
class of nitrogenous compounds called peptones. The pep- 
tones differ from the proteins in that they are more soluble ; 
for instance, a protein such as white of egg is precipitated 
by boiling, while a peptone would not be affected by this 
treatment. 

Mineral matter which constitutes the fourth class of foods 
is present in small amount in almost all portions of animals 
and vegetables which are used as food. When foods of 
this kind are burned, the carbon, hydrogen, oxygen, and 
nitrogen pass off as gases, while the mineral matter remains 
as a solid and is known as the ash. The amount of ash ob- 
tained from a given food is a measure of the amount of 
mineral matter present. If the ash were eaten, only a small 
portion would dissolve and be available for nourishing the 
system. The mineral constituents are in such a form of 
combination in animal and vegetable matter that they can 
be dissolved by th^ blood and deposited in the bones or 



6 PURE FOODS 

teeth where needed. Most natural waters contain a small 
but appreciable amount of mineral matter which is already 
in solution, ready for absorption. If present in unusual 
amount, the water is used expressly for its mineral content 
and is called a mineral water. 

It is evident, therefore, that a food yniist consist of readily 
soluble compounds containing the same chemical elements which 
are found in the human system. 

Food as a source of energy. While food is utilized to 
build up the various organs of the human system and repair 
waste, it must also serve some very different purpose be- 
cause such large quantities are digested and taken into 
the circulation and then expelled again. ^ Investigation 
shows that the chemical elements do not pass out in the 
same form of combination in which they enter the system. 
The greatest difference is found in the amount of oxygen 
in combination with the carbon and hydrogen. These ele- 
ments enter the system combined with very little oxygen, 
and pass out in combmation with the maximum quantity 
for these elements ; that is, as carbon dioxide and water.^ 
It has been demonstrated that this oxygen is taken from 
the air Avhich enters the lungs. Whenever carbon or hydro- 
gen combine with oxygen a large amount of heat is evolved. 
When food is oxidized in the human system this heat is 
liberated and is utilized for maintainmg the normal tem- 
perature of the body. Heat can also be transformed into 
other forms of energy. The steam engine, for instance, 
transforms the heat obtained by burning the coal into me- 
chanical energy, which moves trains or does other useful 
work. In the same way the" energy obtained from the food 

1 A child in growing to manhood consumes from 15 to 20 tons of food. 

2 Hydrogen forms a higher oxygen compound than water (H2O), but this 
compound (hydrogen peroxide, H2O2) cannot exist in contact with animal 
tissues. 



WHAT IS FOOD? 7 

is used in the body to perform muscular work, and to keep 
up the circulation of the blood and other activities of the 
various organs. The system requu-es in the aggregate a 
very large amount of energy for its various activities, all of 
which is obtained from the food. We may therefore define 
food as follows : 

Food must consist of readily soluble compounds containing 
the same chemical elements which are found in the human 
system^ and a considerable amount of energy which caii be 
liberated by oxidation. 

Functions of food. It is evident, therefore, that the food 
serves two functions in the animal body. It serves as the 
material from which the animal structure is built, and it 
also furnishes the energy to keep up the bodily activities 
and temperature, the greater part of the food being used 
for the latter purpose only. The marvelous economy of 
nature is shown in the fact that when any portion of the 
animal structure is worn out and is ready to be discarded, 
it is first decomposed in such a way that its available energy 
is first utilized by the system. Every particle of food, there- 
fore, which is dissolved by the blood gives up its energy 
before it is again eliminated. The energy content of the 
food is therefore the simplest criterion of its value. That 
the taking of food gives strength and energy to the human 
system is a matter of everyday experience. Scientific inves- 
tigation has shown how the energy value of a given food 
can be accurately measured. 

The calorie. As all forms of energ}^ can be transformed 
into each other, it is only necessary to measure the energy 
given out by a food in one of these forms. The heat evolved 
when the food is burned can be readily measured. For this 
purpose the heat is absorbed by water and the increase in tem- 
perature noted. It is evident that with unequal quantities 



8 PURE FOODS 

of heat the same amount of water will be raised to the 
highest temperature by the largest amount of heat. In other 
words, the temperature to which a given quantity of water 
is raised will be a measure of the amount of heat evolved. 
The quantity of water used is one kilogram, which at ordi- 
nary temperatures is very nearly equal to one liter, or 1.056G8 
(juarts. The Centigrade scale is used for measuring the rise 
in temperature. The amount of heat necessary to raise one 
liter of water one degree Centigrade is called a Calorie. 

The calorimeter. For determining the energy value of 
foods, a weighed quantity of the food is placed in a hermet- 
ically sealed bomb, which is fdled with oxygen under pres- 
sure. The bomb is immersed in two liters of water, tlie 
temperature of which is taken ])y means of an accurate ther- 
mometer. A platinum wire in contact with the food is then 
fused by means of an electric current so as to ignite the 
food wliich ])urns in the oxygen surrounding it. Tlie heat 
is absorbed by the water, whicli is kept in constant motion 
by means of a stirring device. The highest temperature 
reached by the thermometer is carefully noted and the 
number of Calories evolved is calculated, a correction being 
introduced for tlie heat retained by the bomb and the vessel 
holding the water. During the experiment the vessel con- 
taining the water and the bomb is protected from loss or 
absorption of heat by insulating covers. The energy value 
obtained in this manner is called the calorific value of the 
food. The instrument used is called a calorimeter. 

1 Using an ordinary (Fahrenheit) thermometer, a Calorie would be very nearly 
equal to the heat necessary to raise the temperature of one quart of water two 
degrees. A much smaller unit, known as the small calorie, is also in use. It is 
the amount of heat necessary to raise the temperature of one cubic centimeter 
of vA'ater one degree Centigrade. A liter contains 1000 ccm. (In order to dis- 
tinguish these units from each other, the large Calorie is spelled with a capital 
C and the small calorie with a small letter. The calorific value of foods is 
generally given in large Calories.) 




Fig. 1. Atwater-Maliler Bomb Calorimeter 
A, bomb immersed in water; B, cover; C, screw-cap; G, screw comiection 
for attacbiiiii to oxygen tank ; //, /, wires for conducting tbe electric current 
for ignition of food placed in platinum cup ; KK, ball-bearings of bard steel 
to avoid friction in screwing cup down ; L, stirring device ; 3^ 0, insulatmg 

vessels toiirevent loss of heat; F, thermometer 



10 PURE FOODS 

The calculation of calorific value. As the calorific value 
of the protein. (5.7), fats (9.3), and carbohydrates (4.1) 
has been carefully determined, the calorific value of a 
given food may be calculated if its chemical composition 
has been determined. In making such a calculation the 
value found for protein in the calorimeter is not used, 
because this constituent of foods is not completely oxi- 
dized in the human system. The value 4.1 is therefore 
used, which represents tlie amount of heat evolved in 
the body. The following values are therefore used in 
calculating the calorific value of a food : 

Protein 4.1 large calories per gram 

Carbohydrates 4.1 large calories per gram 

Fats 9.3 large calories per gram 

It is evident from this table that we obtain the greatest 
amount of heat and energy from fatty foods, but because 
such foods are not easily digested by most people, carbo- 
hydrates are generally consumed in large enough quantities 
to furnish a great deal of the requisite amount of energy. 
By far the most common carbohydrate is starch, so th«at 
starchy foods constitute the bulk of our diet. Because 
protein matter is not completely oxidized, it cannot serve 
economically as a source of energy, and as the elimination 
of its decomposition products from the system by the liver 
and kidneys involves considerable effort, producing dis- 
orders of various kinds, it should not be consumed m 
quantities greater than necessary to keep the tissues of 
the body in good condition. The statement that olive 
oil has a calorific value of 4220 means that when one 
pound of the oil is burned, 4220 calories of heat are 
liberated. The calorific value of sirloin steak is only 
1130 because it contains 62 per cent of water, which 



WHAT IS FOOD? 



11 



gives no energy to the system, its function in a food 
being simply to hold soluble matter in solution, rendering 
digestion more easy. 

Composition of foods. It is evident that the essential 
characteristics of a food can be indicated by giving the 
percentage of water, mineral matter, fat, carbohydrates, 
and protein present, as well as the calorific value. The 
following table gives this data for the edible portion of a 
number of common articles of food. The foods are in the 
raw state unless otherwise designated. 

TABLE I 
Composition and Calorific Valuk of Common Foods 



Food as purchased 



Beef 

Corned 

Porter-house steak 
Sirloin steak . . . 
Kound steak . . . 

Ribs 

Rump 

Lavib 

Leg, hind . . , . 
Mutton 

Leg, hind . . . . 

Loin chops . . . 

Pork 

Bacon, smoked . . 

Ham, fresh . . . 

smoked . . 

Loin chops . . . 
Salt pork .... 

Tenderloin . . . 



Refuse 


Water 


Per 
cent 


Per 
cent 


8.4 


49.2 


12.7 


52.4 


12.8 


54.0 


7.2 


60.7 


20.8 


43.8 


20.7 


45.0 


17.4 


52.9 


18.4 


51.2 


16.0 


42.0 


1.1 


17.4 


10.7 


48.0 


13.6 


34.8 


19.7 


41.8 




7.9 




66.5 



Protein 



Per 

cent 

14.3 
19.1 
16.5 
19.0 
13.9 
13.8 



15.9 

15.1 
13.5 

9.1 
13.5 
14.2 
13.4 

1.9 
18.9 



Fat 



Per 
cent 

23.8 

17.9 

16.1 

12.8 

21.2 

20.2 



13.6 

14.7 

28.3 

62.2 
25.9 
33.4 
24.2 
86.2 
13.0 



Carbo- 
hydi-ates 



Per 

cent 



Mineral 
matter 



Per 

cent 

4.6 

0.8 

0.9 
1.0 
0.7 
0.7 



0.9 

0.8 
0.7 



4.1 
0.8 
4.2 
0.8 
3.9 
1.0 



Calorific 
value 



Calories 

1245 
1100 
975 
890 
1135 
1090 



860 

890 
1415 

2715 
1320 
1635 
1245 
3555 
895 



12 



PUIiE FOODS 



TABLE I (Continued) 
Composition and Calorific Valie ov Common Foods 



Food as purchased 


Uefuse 


Water 


Protein 


Fat 


Carbo- 
hydrates 


Mineral 
matter 


Calorific 
value 


Veal 


Per 
cent 


Per 
cent 


Per 
cent 


J'er 
cent 


Per 

cent 


Per 

cent 


Calories 


Breast 


2L3 


52.0 


15.4 


11.0 




0.8 


745 


Leg 


14.2 


00.1 


15.5 


7.9 




0.9 


625 


Leg cutlets 


3.1 


08.3 


20.1 


7.5 




1.0 


695 


Poultry 
















Chicken, bi-oilers . . . 


41.G 


43.7 


12.8 


1.4 




0.7 


305 


Turkey 


22.7 


42.4 


16.1 


18.4 




0.8 


1060 


Fish 
















Cod, fresh, dressed . . 


29.9 


58.5 


11.1 


0.2 




0.8 


220 


salt 


24.9 


40.2 


16.0 


0.4 




18.5 


325 


Halibut, steak or sections 


17.7 


01.9 


15.3 


4.4 




0.9 


475 


Lobsters 


()1.7 


30.7 


5.9 


0.7 


0.2 


0.8 


145 


Mackerel, whole . . . 


44.7 


40.4 


10.2 


4.2 




0.7 


370 


Oysters, "solids" . . . 




88.3 


6.0 


1.3 


3.3 


1.1 


225 


Perch, yellow, dressed . 


35.1 


50.7 


12.8 


0.7 




0.9 


275 


Salmon, canned . . . 




(13.5 


21.8 


12.1 




2.6 


915 


Shad, whole 


50.1 


35.2 


9.4 


4.8 




0.7 


380 


Eggs and Dairy Products 
















Butter 




11.0 


1.0 


85.0 




3.0 


3410 


Cheese, full cream . . 




34.2 


25.9 


33.7 


2.4 


3.8 


1885 


skim milk . . 




45.9 


31.5 


16.5 


2.0 


4.1 


1320 


Cream 




74.0 


2.5 


18.5 


4.5 


0.5 


865 


Eggs, white 




86.3 


12.8 


0.4 




0.5 


250 


yolk 




50.0 


16.0 


33.0 




1.0 


1705 


whole 


11.2 


65.5 


13.1 


9.3 




0.9 


635 


Milk, whole 




87.1 


3.2 


4.0 


5.0 


0.7 


325 


skimmed .... 




90.5 


3.4 


0.3 


5.1 


0.7 


165 


butter 




91.0 


3.0 


0.5 


. 4.8 


0.7 


160 


condensed . . . 




26.9 


8.8 


8.3 


54.1 


1.9 


1430 


Cereals 
















Barley 




11.9 


10.3 


2.0 


73.3 


2.5 


1640 


pearled .... 




11.3 


8.4 


1.0 


78.3 


1.0 


1650 


Buckwheat flour . . . 




13.6 


6.4 


1.2 


77.9 


0.9 


1605 



WHAT IS FOOD? 



13 



TABLE T (CoNTiNrED) 
Composition and Calouikk; A^aluk of Common Foods 



Fooil ius imrcliused 


Uefuse 


Wiitei- 


rroteiii 


Fut 


("arbo- 
liytl rates 


Mineral 
inattei- 


Calorific 
value 


Cereals {Continued) 


Prf 

cent 


Per 

(■('lit 


Per 

cent 


Per 

ce)ii 


Per 

cent 


Per 

cent 


(Hlnries 


Corn meal 




12.5 


9.2 


1.9 


75.4 


1.0 


1635 


Grahtiiii flour. 






11.3 
10.3 


13.3 
13.4 


2.2 
0.9 


71.4 
74.1 


1.8 
1.3 


1645 


Macaroni, vermicelli, ek 


1645 


Oatmeal 




1- ^ 
i.i 


16.7 


7.3 


66.2 


2.1 


1800 


Kice 




12.3 


8.0 


0.3 


79.0 


0.4 


1620 


Rye flour 




12.9 


6.8 


0.9 


78.7 


0.7 


1620 


Wheat flour, patent 
















roller process 
















high grade and med. 




12.0 


11.4 


1.0 


75.1 


0.5 


1635 


low grade .... 




12.0 


14.0 


1.9 


71.2 


0.9 


1640 


whole wheat . . . 




11.4 


13.8 


1.9 


71.9 


1.0 


1650 


Bread and Pastnj 
















Bread, brown .... 




43.6 


5.4 


1.8 


47.1 


2.1 


1040 


graham . . 








35.7 


8.9 


1.8 


52.1 


1.5 


1195 


rve 








35.7 


9.0 
9.2 


0.6 


53.2 


1.5 


1170 


white . . . 








35.3 


1.3 


53.1 


1.1 


1200 


whole wheat 








38.4 


9.7 


0.9 


49.7 


1.3 


1130 


Cake ...... 








10.1) 


6.3 
11.3 


9.0 


63.3 


1.5 


1630 


Oyster crackers 








4.8 


10.5 


70.5 


2.9 


1910 


Soda crackers . . 








5.9 


9.8 


9.1 


73.1 


2.1 


1875 


Vegetables 
















Beans, baked .... 




08.9 


6.9 


2.5 


19.6 


2.1 


555 


dried 




12.6 


22.5 


1.8 


59.6 


3.5 


1520 


Lima, shelled. . 




68.5 


7.1 


0.7 


22.0 


1.7 


540 


strino- .... 


7.0 


83.0 


2.1 


0.3 


0.9 


0.7 


170 


» 

Beets 


20.0 


70.0 


1.3 


0.1 


7.7 


0.9 


160 


Cabbage 


15.0 


77.7 


1.4 


0.2 


4.8 


0.9 


115 


Celery 


20.0 


75.6 


0.9 


0.1 


2.6 


0.8 


65 


Corn, sweet, green, edi- 
















ble portion . . 




75.4 


3.1 


1.1 


19.7 


0.7 


440 


canned . .^ . . 




76.1 


2.8 


1.2 


19.0 


0.9 


430 



14 



PURE FOODS 



TABLE I (Concluded) 
Composition and Calorific Value of Common Foods 



Food as purchased 


Refuse 


Water 


Protein 


Fat 


Carbo- 
hydrates 


Mineral 
matter 


Calorific 
value 


Vegetables ( Continued) 


Per 
cent 


Per 

rent 


Per 

cent 


Per 

cent 


Per 

cent 


Per 

cent 


Calories 


Cucumbers 


15.0 


81.1 


0.7 


0.2 


2.6 


0.4 


65 


Lettuce 


15.0 


80.5 


1.0 


0.2 


2.5 


0.8 


65 


Mushrooms 




88.1 


3.5 


0.4 


6.8 


1.2 


185 


Muskmelons 


50.0 


44.8 


0.3 




4.6 


0.3 


80 


Onions 


10.0 


78.9 


1.4 


0.3 


8.9 


0.5 


190 


Parsnips 


20.0 


66.4 


1.3 


0.4 


10.8 


1.1 


230 


Peas, dried 




9.5 


24.6 


1.0 


62.0 


2.9 


1565 


shelled 




74.6 


7.0 


0.5 


16.9 


1.0 


440 


green, canned . . 




85.3 


3.6 


0.2 


9.8 


1.1 


235 


Potatoes, Irish .... 


20.0 


62.6 


1.8 


0.1 


14.7 


0.8 


295 


sweet . . . 


20.0 


55.2 


1.4 


0.6 


21.9 


0.9 


440 


Spinach 




92.3 


2.1 


0.3 


3.2 


2.1 


95 


Squash 


50.0 


44.2 


0.7 


0.2 


4.5 


0.4 


100 


Succotash, canned . . 




75.9 


3.6 


1.0 


18.6 


0.9 


425 


Tomatoes 




94.3 


0.9 


0.4 


3.9 


0.5 


100 


canned . . . 




94.0 


1.2 


0.2 


4.0 


0.6 


95 


Turnips 


30.0 


62.7 


0.9 


0.1 


5.7 


0.6 


120 


Watermelons .... 


59.4 


37.5 


0.2 


0.1 


2.7 


0.1 


50 


Fruits 
















Apples 


25.0 


63.3 


0.3 


0.3 


10.8 


0.3 


190 


Apples, dried 












28.1 


1.6 


2.2 


66.1 


2.0 


1185 


Apricots, dried 












29.4 


4.7 


1.0 


62.5 


2.4 


1125 


Bananas . . 










35.0 


48.9 


0.8 


0.4 


14.3 


0.6 


260 


Dates, dried . 










10.0 


13.8 


1.9 


2.5 


70.6 


1.2 


1275 


Figs, dried 












18.8 


4.3 


0.3 


•74.2 


2.4 


1280 


Grapes . . . 










25.0 


58.0 


1.0 


1.2 


14.4 


0.4 


295 


Lemons . . . 










30.0 


62.5 


0.7 


0.5 


5.9 


0.4 


125 


Oranges . . . 










27.0 


63.4 


0.6 


0.1 


8.5 


0.4 


150 


Pears . . . 










10.0 


76.0 


0.5 


0.4 


12.7 


0.4 


230 


Raisins . . . 










10.0 


13.1 


2.3 


3.0 


68.5 


3.1 


1265 


Easpberries . 












85.8 


1.0 




12.6 


0.6 


220 


Strawberries . 










5.0 


85.9 


0.9 


0.6 


7.0 


0.6 


150 



WHAT IS FOOD? 



15 



EXPERIMENTS 



1. Starch test. Place a gram or two of starch in a beaker or por- 
celain mortar, add a little water, and stir so as to make a thin paste. 
Stir the starch jiaste, while pouring on it 100 ccm. of boiling water. 
Dilute the solution with an equal volume of water. Place a few 
cubic centimeters of the starch solution in a beaker or test tube and 
add a few drops of iodine solution.^ The blue color produced is a 
very delicate test for starch. Various articles of food may be tested 
in this manner for starch, such as flour, potatoes, vegetables, etc. The 
test may sometimes be obtained without boiling with water. 

2. Test for reducing sugar. Prepare Fehling's solution as follows : 
I. Dissolve 7 gm. (about i oz.) of crystallized sulphate of copper in 
100 ccm. of water and place in a bottle. II. Dis- 
solve 34.6 gm. of crystallized Rochelle salt in 
45 ccm. of water, also 25 gm. of caustic soda 
in 40 ccm. of water. Mix these two solutions, 
dilute to 100 ccm., and preserve in a bottle 
properly labeled. Equal portions of solutions 
I and II are mixed when required for making 
a test. 

Test various food products for sugar by 
means of Fehling's solution. Honey, sirup, 
grape juice, or other fruit juices may be used. 
Dissolve a few drops of these foods in water, 
heat to boiling in a beaker or other suitable 
vessel, and add a few drops of the mixed 
Fehling's solution. A bright red precipitate 
indicates reducing sugars, such as dextrose, 
levulose, etc. Cane sugar does not give this 
test unless it is first boiled with acid. 

3. Test for fatty acids. Add a few drops of phenolphthalein- to 
50 ccm. of alcohol in a small bottle or flask. Add a diluted solution of 
caustic soda drop by drop until the alcohol is colored red. Introduce 
a few cubic centimeters of olive oil, butter, lard, or other fat and 
shake vigorously. If the fat or oil is at all rancid, the red color 




Fig. 2. Tripod and 
Wire Gauze arranged 
for boiling Liquids 
with the Buusen 
Buruer 



1 The method of i>repariiig this and other reagents will he found in the 
Appendix, page 189. 

2 One tenth gram of the solid dissolved in 100 ccm. of alcohol. 



16 PUKE FOODS 

will gradually fade because the alkali is neutralized by tlie free 
fatty acids. 

4. Test for organic nitrogen. Introduce a small portion of dry meat, 
wheat flour, white of egg, or other nitrogenous food into a test tube. 
Add a piece of metallic sodium ^ or magnesium about the size of a 
pea. Heat to redness in the flame of a Bunsen burner. AVhen cool 
dissolve the contents of the test tube in water and add a few drops 
of solutions of ferric chloride and ferrous sulphate and then add 
hydrochloric acid until the solution is acid. A deep blue color in- 
dicates the presence of nitrogen in the food tested. 

5. Test for mineral matter. Place several grams, of flour, i)otato, 
or other food in its natural state in a platinum or porcelain dish and 
heat over a Bunsen burner until the food begins to burn. The black 
color is evidence of the presence of carbon. Continue the heating 
until only a white residue remains. This is the ash of the food and 
contains the mineral matter of the food. Add a little water and 
warm and moisten a piece of red litmus paper with the solution. 
A blue color indicates the presence of sodium or potassium carbonate 
or other salts, which are generally jtresent in considerable quantities 
in vegetables. The ash may also be tested for magnesium, calcium, 
iron, and aluminum, which are usually present in vegetables. 

6. Digestion of protein. To 9 ccm. of dilute hydrochloric acid add 
291 ccm. of distilled water. Dissolve ^L gm. of pepsin in 150 ccm. 
of the diluted acid. Boil a fresh egg for fifteen minutes. Remove 
the white, press it through a fine sieve, and place 10 gm. in a bottle 
of suitable size. Add 35 ccm. of the diluted acid and rub the allni- 
men fine with a glass rod. Add 5 ccm. of the pepsin solution. 
Cork the bottle and place in water kept at 52° C. (126° F.). Allow to 
remain for several hours, shaking occasionally. The albumen has now 
been converted into peptone, as may be shown by the following tests. 
Boil a portion of the solution and to another portion add zinc sul- 
phate. Repeat these tests with a solution of the uncooked white of 
egg in water and observe the difference. Peptone may be precipitated 
by the addition of a solution of tannin. 

7. Test for solids and mineral matter of milk. Place 10 ccm. of 
milk in a porcelain dish. Evaporate to dryness on the water bath. 
Only the water passes off during the evaporation. The residue 

1 Metallic sodium must not be allowed to come into contact with water, as 
it may explode. It should be kept under kerosene. 



WHAT IS FOOD? 17 

constitutes the solids of the milk, which give it its food value. Heat 
the dish with the Bunseu burner until the milk solids begin to burn. 
If the operation were carried out in a calorimeter so that the heat 
produced would pass into the water, the calorific value of the milk 
would be obtained. Continue the heating until the solids are com- 
pletely burned and only a nearly white ash remains. This ash may 
be tested as directed in the preceding experiment. 



CHAPTER 11 

WHAT IS PURE FOOD? 

Pure food. The term "pure food" can be defined only 
after long experience with all kinds of foods and very ex- 
hanstive scientific and practical investigation. While much 
work of this kind has been completed, many investigations 
are being carried on at the present time in order to deter- 
mine which foods are pnre and which are impnre. Food 
producers and manufacturers have by no means arrived 
at fixed standards of excellence for their products. Many 
new foods are being constantly placed on the market, in 
regard to which no reliable opinion can be given until they 
have been thoroughly tested. From the consumer's stand- 
point there is such a great difference in individual consti- 
tution and condition that Avhat is perfectly harmless and 
even beneficial to one man may be poisonous to another. 
Our present definitions of a pure food must therefore be 
tentative and subject to change, as time goes on, to meet 
the requirements of experience, scientific investigation, and 
the changing conditions of our food supply and manufac- 
ture. INIany foods must be classed as pure, even though 
they are injurious to some people. 

Adulterated foods. In general it must, of course, be 
assumed that a pure food is one which, properly consumed, 
will nourish a healthy human being without producing dis- 
tress of any kind, sickness, or death. The definition of a 
pure food indicates the method of differentiating between 
foods possessing these qualities and injurious ones. Foods 

18 



WHAT IS PURE FOOD? 19 

are also classed as adulterated if the purchaser is deceived 
as to their natural origin or constituents, or if they are 
below standard in nutritive value. Such standards are 
fixed by law, and an otherwise pure and wliolesonie food 
which does not conform to such standards is classed as 
adulterated. The following essentials of a pure food liave 
been embodied in most legal definitions. 

Long-used foods, pure. In the first place, a food is pure 
if it has been in common use for a long time. While such 
a food may be injurious under certain circumstances, and 
indeed frequently is, it is not called impure because its 
peculiarities are a matter of common knowledge. There is 
no deception or fraud involved in the sale of such an article. 
If a person is injured by eating it, it is held to be his own 
fault in that he is ignorant of its properties. For example, 
many people have died from the excessive consumption of 
pickles and vinegar. Excessive quantities of salt are inju- 
rious, so that the eating of much salt meat leads to serious 
disorders. Although sugar is one of the best foods we have, 
its excessive consumption is hijurious. No one would think 
of calling these well-known foods impure. Any attempt 
to restrict their sale or consumption would certainly fail. 

Substitution. The attitude of the public toward a new 
food product is entirely different. If it can be shown to be 
injurious toward even a very small proportion of those who 
eat it, it is apt to be declared unwholesome. This is mainly 
due to the fact that the public have not learned by long- 
experience just what the circumstances are under which it 
is injurious. Opposition to a new food is especially violent 
when it is sold under the name of a common, long-used 
food or mixed with such a food product. Such a practice 
constitutes a moral as well as a legal fraud. A food sold 
in this manner is called an impure or adulterated food, even 



20 PURE FOODS 

though it may be entirely harmless and nutritions. It is 
being generally recognized tliat such a practice is poor 
policy from a business standpoint. INIany examples of this 
kind of adulteration may be cited. Cottonseed oil has been 
largely sold as olive oil. A large number of the sirups on 
the market are composed in large part of glucose. The 
l)est California wines have been sent to France, placed in 
bottles bearing the labels of well-known French brands of 
wine, and returned to this country. The inferior California 
wines have been sold under their own names. The Cali- 
fornia wine grower now finds that his product has a bad 
reputation, even though he produces wine equal to any 
grown in France. In the same manner, glucose, although 
an excellent food product, is generally considered injurious 
simply because it has always been sold fraudulently, and 
the public has not had the opportunity to use it knowingly 
and learn its merits. Many people have long used cotton- 
seed oil under tlie name of olive oil and prefer it to the 
real article, but not under the name cottonseed oil. 

Poisonous constituents. Every food is, of course, con- 
sidered impure and adulterated if it contains constituents 
which may correctly be classed as poisonous, such as arsenic, 
lead, copper, etc. A number of chemical compounds have 
been used as preservatives which are certainly poisonous, 
while a few preservatives have been discovered which do 
not seem to have any deleterious influence on the human 
system when consumed in small quantities. The same 
statement can be made of the aniline dyes. Some of these 
brilliant coal-tar colors are highly poisonous, while others 
have been fed to animals in large quantities and even in- 
jected directly into the blood without any ill effect. No ill 
effect has been observed Avhen these dyes have been con- 
sumed in large quantities by human beings. Foods which 



WHAT IS PUKE rOOD? 21 

have been derived from diseased or decayed plants or ani- 
mals are classed as impure or adulterated. Such foods may 
contain the germs of disease as well as many poisonous 
substances which are known to be produced during diseases 
or in the process of decay. Even if such foods do not con- 
tain any poisonous constituents, everybody has such a strong- 
natural aversion to diseased or decayed matter that the 
sale of such food is violently resented by the public. That 
partially decayed food is not necessarily injurious is evident 
from the large consumption of the so-called fermented cheese 
and tainted venison and other meat. 

Reduction of food value. In addition to the requirement 
that pure foods shall contahi none of the classes of poison- 
ous ingredients already named, a pure food is defined as 
one from which none of the nutritious constituents have 
been withdrawn or the food value lowered in any manner. 
For instance, milk from which the cream has been removed 
is classed as adulterated unless it is sold as skim milk. 
The addition of Avater is also a fraud. 

Deception. Pure food must not be coated, colored, or 
painted so as to appear better than it really is. For instance, 
milk is sometimes colored to make a poor product appear 
richer in cream. Cheap candies are often coated with 
shellac varnish so as to imitate the appearance of choco- 
late, which they really do not contain. Both of these 
practices are condemned as fraudulent. The same is true 
of the addition of coloring matter to butter; while this 
practice is illegal, it is not suppressed because most people 
prefer yellow butter, and no fraud is involved unless oleo- 
margarine is colored to imitate butter and is sold as such. 

Misleading labels. By legal enactment in many states, 
a food to be classed as pure must be sold under a name or 
label which correctly gives its composition or the place or 



22 PUEE FOODS 

firm by whom it is produced. To prove that there was 
nothing injurious in its composition would not save a mer- 
chant from prosecution for selHng a food under a misleading 
label. The sale would be fraudulent because the purchaser 
would be getting something different from what he sup- 
posed he was getting for his money. 

Legal standards. In general, a food to be called pure 
must conform in every particular to the law. In some cases 
the words '' pure " and " impure " or '' adulterated " acquire 
a very unusual meaning by legal enactment. For instance, 
the laws of many states specify that milk must contain 12 per 
cent of solids. Some cows give milk containing a smaller 
proportion of solids. The sale of such milk is illegal, even 
if it is shown to have been sold in absolutely the same con- 
dition in which it came from the cow. This is an example 
of an absolutely pure natural product declared by law to 
be impure and adulterated. Of course the standard fixed 
by law is slightly lower than the average composition of 
pure cow's milk. 

Adulterated food. Food is impure or adulterated, there- 
fore, when it contains injurious constituents of any kmd, 
when it is below the standard in food value, when sold 
under some form of fraud or deception, or when it does 
not conform in some respect to pure-food laws. The words 
'' impure " and " adulterated " as applied to foods very 
rarely imply the presence of what are commonly considered 
poisonous constituents. 



CHAPTER ITT 

STANDARD RATIONS AND THE COST OF FOOD 

The daily ration. If the amount of the various kinds of 
food consumed during twenty-four hours by a human being 
under normal conditions is weighed, and the total amount 
of each of the food constituents is calculated, the result 
gives what is known as the daily ration. For a given age 
or condition of life this is found to be surprisingly constant, 
not only with respect to the total amount of food taken, but 
also with reference to the relative amounts of fats, car- 
bohydrates, and protein. The total calorific power which 
represents the energy which the system can obtain from 
the food is also very constant. 

A balanced diet. If the amount and kind of food is not 
well selected, an excess of one or more of the essential 
constituents of food will be present and must be elimi- 
nated to the detriment of the system. For instance, a 
diet composed largely of meat will contain more protein 
matter than is required to keep the tissues in good con- 
dition. It is necessary with such a diet to consume this 
excess of protein matter in order to obtain the proper 
amount of fats and carbohydrates. Such a diet is not 
well balanced. 

TJie stmidard ration gives the quantities of fats, carbohy- 
drates, and protein found to he just sufficient to sustain a 
human being under given conditio7is in normal health and 
activity. 

23 



24 PUPvE FOODS 

The standard ration. The daily ration found by most 
investigators contains 100 gm. of protein, 100 gm. of fat, 
and 420 gm. of carbohydrates, or a total of 620 gm. These 
weights refer to the solid matter only of the food. In its 
ordinary condition about three times this amount would be 
required because ordinary food contains a large amount of 
water. Expressed in ordinary or avoirdupois weights, this 
standard ration would require 3^ oz. of protein, 31^ oz. of 
fat, and 15 oz. of carbohydrates, or a total of 22 oz. of 
solid food, which is equivalent to about 4 pounds of ordi- 
nary food. The 3000 calories of energy given by this 
amount of food, if liberated as heat, are capable of raising 10 
gallons of water from the ordinary temperature to the boil- 
ing point ; if used as mechanical energy, 2000 pounds, or 
one ton, could be raised 4500 feet, or very nearly a mile. 
It seems well-nigh incredible that the food consumed by 
the average human being during twenty-four hours should 
liberate so much energy. 

Interchangeable foods. While a great many of the tissues 
of the body can be built up and repaired only by protein, 
which for this reason is of the greatest importance in the 
diet, this food material can also furnish energy and there- 
fore serves a double function in the economy of nature. 
It can therefore replace to a certain extent fats and carbo- 
hydrates in the diet. To a still greater extent, fats and 
carbohydrates are mutually interchangeable. It is there- 
fore possible to live on a diet in which the proportion of 
the food constituents is very different from that in the stand- 
ard or normal ration. There seems also to be a very great 
difference in individuals, so that considerable variation is 
often necessary in order to suit idiosyncrasies of appetite, 
digestion, and assimilation. The consumption of excessive 
quantities of protein seems to be undesirable. 



STANDARD RATIONS AND COST OF FOOD 25 

Rations for children. During periods of unusual activity 
a much larger amount of food is consumed, while the aged 
and children consume less. The ration for children is given 
in Table 11. It will be observed that the amount of pro- 
tein in the diet of the cliild is relatively larger than in that 
for the adult. The child one year and a half old requires 
24 per cent of its food to be protein, while the adult re- 
quires only 16 per cent. The child is building up a new 
body structure, while the adult is simply making repairs. 

TABLE II 
Rations for Ciiiloren 



Age 


Protein 


Fat 


Carbo- 
liydrates 


Calories 




(rfams 


(irainn 


drams 




11 years .... 


42.5 


35 


100 


910 


2 years .... 


45.5 


30 


no 


972 


3 years .... 


50 


38 


120 


1050 


4 years .... 


53 


41.5 


135 


1157 


5 years .... 


56 


43 


145 


1224 


8-0 years . . . 


GO 


44 


150 


1270 


12-13 years . . . 


72 


47 


245 


1737 


14-15 years . . . 


79 


48 


170 


1877 



Special rations. Table III gives a number of special 
rations which show how trained athletes are capable of 
utilizing an abnormally large amount of energy derived 
from food, while the aged cannot utilize as much. As fats 
and oils produce the largest amount of heat, these foods 
are consumed in large quantity by the inhabitants of the 
coldest climates of the earth, while they are avoided by those 
living in the torrid zone. Men doing a large amount of mus- 
cular work also consume fats for the production of energy. 



26 



PUEE FOODS 



TABLE III 
Special Rations 



Age or Employment 


Protein 


Fat 


Carbo- 
hydrates 


Calories 


Average adult ...... 

Average of seven boat crews . 

Football team 

United States. Army .... 

Old man 

Old woman 


Grams 
100 
155 
181 

85 
92 
80 


Grams 
100 
177 
292 
280 
45 
49 


Grams 
420 
440 
577 
500 
332 
266 


3030 
4085 
5740 
4944 
2149 
1875 



Excessive consumption of protein. A considerable amount 
of evidence lias been brought forth to show that the amount 
of protein in the ordinary diet is too large. Men in active 
life and also trained athletes have been fed for long periods 
on diets containing half the usual amount of protein, re- 
maining vigorous and in good health continually, and in 
some cases even showing a very marked increase in strength 
and endurance. 1 While the number of experiments con- 
ducted has not been sufficient to prove conclusively that 
the amount of protein consumed is unnecessarily large, the 
evidence at hand renders it very probable that Ave are 
consuming about twice as much meat and other highly 
nitrogenous food as is necessary. The stimulating effect 
of such a diet undoubtedly accounts for the tendency of 
mankind for centuries to consume large quantities of meat, 
while only recently has scientific investigation begun to 
show that the carbohydrates and fats of our diet give the 
greater endurance and strength. 

Coefficient of digestibility. It must be borne in mind when 
considering dietaries that the food consumed is seldom or 

1 See Chittenden, The Nutrition of Man. 



STANDAED RATIONS AND COST OF FOOD 27 

never completely digested, although the percentage so 
utilized by the system is in many cases surprisingly large, 
as may be observed from an inspection of Table IV. 

TABLE IV 
Coefficient of Digestibility of Nutrients in Foods 



Food 


Protein 


Fats 


Carbo- 
hydrates 


Bananas 

Beans 

Beef 


Per cent 
85 
80 
98 
88 
83 
97 
83 
98 
75 

91 


Per cent 
90 

98 
98 
90 

95 

98 

95 


Per cent 
90 

97 


Bread, white 

whole wheat .... 

Milk and butter ...... 

Peas ... 


98 
95 
98 
95 


Pork 




Potatoes, Irish ...... 


99 
98 


Average common foods . . . 


98 



The percentages given in this table do not show the ease 
with which these foods are digested. They simply give the 
proportion of the food which is finally digested, whether 
the effort on the part of the digestive system is great or 
small. It is also assumed that the food is properly masti- 
cated and that excessive amounts are not consumed. It may 
be stated, in general, that the protein matter of vegetables 
is not as digestible as that of meats. 

The method of calculating the daily ration from a mixed 
diet is shown in Table V. 

A record of the amount of each article of food consumed 
during a week was kept and the weight of each of the 
constituents calculated from the percentage composition 
of the food, and. also the total calorific value. Allowance 



28 



PURE FOODS 



TABLE V 
Week's Food for Four Adults 



Food 



Sugar 

Prunes 

Corn flakes . . . 

Fish •. 

Butter 

Lima beans . . . 

Malt 

Uneedas .... 
Lettuce .... 

Eggs 

Blackberries . . 

Beef 

Condensed milk . 

Milk 

Onions 

Strawberries . . 
Cauliflower . . . 
Potatoes .... 

Bread 

Pretzels .... 
Leg of lamb . . 
Oatmeal .... 
Herring .... 
Flour 

Total per week 

Total inm day . 

For one adult . 

Standard ration 



Pounds 



101 

2 
1 

3 
1 

1 



6 
3 
1 
4 

2 
1 
i) 

''^ 

21 



Protein 



17.2 

40 
231 

13.5 

33.3 

50 

22 

7 

100 

21 
172 

22 

400 

3 

14 
3 

48 
120.3 

44 
270 
140 
115 
450 



2,418 

345 

8(5 

100 



• 10 

77 

1,155 

2.7 

5 

12 

1.2 
80 
15 
64.4 
28 
560 
.8 
10 

.8 
24 
132 
24 
270 
66 
38 
45 



2,599 

371 

93 

100 



Cavboliy 
drates 



drama 

4,756 

564 

340 



131.2 
338 
150 
17 

132 

70 
696 

20 

88 

20 
414 
718.5 
300 

610 

3,042 



12,412 

1,773 

443 

420 



Calorie> 



19,500 

2,378 

1,655 

1,650 

10,512 

467 

1,645 

800 

110 

1,190 

780 

1,300 

600 

10,000 

210 

520 

210 

1,950 

3,615 

1,600 

3,620 

3,720 

825 

14,805 



84,662 

12,095 

3,024 

3,030 



must be made in preparing snch a table for unconsumed 
pcjrtions and the necessary waste in preparing food for the 
table. From the total of each colnmn the amonnt per day 



STANDARD RATIONS AND COST OF FOOD 29 

for eaeli individual can be calculated. The daily ration in 
this case was 86 gm. of protein, 93 gni. of fats, 443 gni. of 
carbohydrates, and 3024 calories, which is very nearly identi- 
cal with the standard ration, although a little low in protein. 
Comparative cost of foods. It is evident that a given food 
constituent, such as protein, can be obtained from a large 
variety of foods. On account of the difficulty of producing 
a given food, its scarcity, or a very desirable flavor, the 
cost of the same amount of protein may vary within very 
wide limits. In order to show the great difference in the 
cost of foods, Table VI has been prepared. The cost of a 
sufficient amount of eacli food to give 3000 calories has been 

TABLE VI 
Cost of a Daily Ration ok a SiN(iLK Food 



Food 


Price 


Cost of 3000 
calories 


jri()\u" 


Ctnta 
31 per pound 
5 per pound 

8 per jiound 
5 per pound 

20 per pound 

9 per quart 
40 per dozen 
18 per pound 

14 per pound 
80 per bushel 

15 per pound 

14 per pound 
13 per pound 
35 per pound 

250 per gallon 

15 per dozen 
12 per dozen 


Ccutii 
6 3 


Oatmeal 


8 


Pvice 

Sugar 

Beef 


15 

8 

58 


Milk 

Eoo-S 


38 
184 


Cheese 

Fish 

Potatoes . 


20 

101 

12 


Cauliflower 

Onions 


215 
215 




250 


Butter 


29 


Olive oil 


23 


Bananas 

Oysters 


40 
553 



30 



PURE FOODS 



calculated. As this is the amount needed during twenty- 
four hours by the average adult, the figures given show the 
cost of a day's ration of each article of food. 

While living on a single article of food for even one day 
would not be very desirable, and would be actually done 
only under very unusual conditions, the calculation of the 
cost of such a day's ration shows very clearly the compara- 
tive cost of tlie various articles of food. A study of this 
list shows that the price per pound gives very little idea 
of the comparative economy of buying a given food. Beef, 
for instance, at 20 cents a pound is a very much cheaper 
food than fish at 14 cents per pound, snice, when buying 
beef, 58 cents will buy as much nutritive value as $1.01 
will purchase when buying fish. The cheapest articles 
of food cannot always be purchased, however, because 
the proper balance between the fats, carbohydrates, and 
protein must be maintained, and some foods must be 
used on account of their beneficial effect on the digestive 
system. 

The following table shows liow the same nutritive value 
as well as the correct proportion of the various food constit- 
uents can be obtained at a very great difference in cost. 

TABLE VI I 
Cost of a Day's Food of Beefsteak, Potatoes, and Butter 



Food 


Cost 


Protein 


Fat 


Curbo- 
hydrates 


Mineral 
matter 


Calories 


Steak, 11 lb. . . 
Potatoes, 5 lb. . . 
Butter, 2 oz. . . 


Cents 
30 

8 
5 


Grams 
87 
40 


Grams 
52 

48 


Grams 
339 


Grams 

4 

20 


937 

1630 

450 


Total .... 


43 


127 


100 


339 


24 


3017 



STANDARD RATIONS AND COST OF FOOD 31 

TABLE VII (Continued) 
Cost of a Day's Food of Eggs, Bread, and Butter 



Food 


Cost 


Protein 


Fat 


Carbo- 
hydrates 


Mineral 
matter 


Calories 


Eggs, 1 doz. . . 
Bread, 1| loaves . 
Butter, 2 oz. . . 


Cents 

38 

6 

5 


Grams 
66 

48 


Grains 
52 
4.5 

48 


Grams 
325 


Grams 
5 
9 


838 

1650 

450 


Total .... 


49 


114 


104.5 


325 


14 


2938 



Cost of a Day's Food of Fish, Potatoes, Butter, and 
Olive Oil 



Food 


Cost 


Protein 


Fat 


Carbo- 
hydrates 


Mineral 
matter 


Calories 


Bluefish, 2 lb. . . 
Potatoes, 4f lb. . 
Butter, 2 oz. . . 
Olive oil, 2 oz. 


Cents 

40 

8 

5 

5 


Grams 
86 
39 


Grams 
5 

48 
54 


Grams 
328 


Grams 

4.7 

17.8 


410 

1575 

450 

528 


TOTAI 


58 


125 


107 


328 


22.5 


2963 



Cost of a Day's Food of Oysters, Bread, Butter, and 
Olive Oil 



Food 


Cost 


Protein 


Fat 


Carbo- 
hydrates 


Mineral 
matter 


Calories 


Oysters, 2i lb. . . 
Bread, 1^ loaves . 
Butter, 2 oz. . . 
Olive oil, 2 oz. . 


Cents 

107 

6 

5 

5 


Grams 
65 
42 


Grams 
9.1 
3.9 

48 

54 


Grams 

35.8 

284.5 


Grams 
6.5 

7.8 


575 

1440 

450 

528 


Total .... 


123 


107 


115 


320.3 


14.3 


2993 



32 



PUPvE FOODS 



TABLE Yll (Concluded) 
Cost of a Day's Food of Milk, Bread, and Butter 



Foo.l 


Cost 


Protein 


Fat 


Carbo- 
hydrates 


Mineral 
matter 


Calories 


Milk, 21 qt. . . . 
Bread, 1^ loaves . 
Butter, 1 oz. . . 


Cents 

18 

G 

2 


Grams 
73 
40 


Grams 
69 

3.7 
30 


Grams 

88 

2(37 


Grams 
13.4 

7 


1430 

1350 

225 


Tot AT 


20 


113 


102.7 


355 


20.4 


3005 



CHAPTER IV 

MILK 

Importance of milk as a food. Milk is one of tlie most 
largely used of liumaii foods. The eity of New York uses 
2,000,000 quarts of milk per day ; 500,000 gallons come 
pouring into the city every twenty-four hours, and are 
consumed by the population. If this amount of milk were 
divided equally, every person would have one-half quart 
of milk per day. This amount is sufficient to constitute 
10 per cent of the standard daily ration, and when we con- 
sider that not over half of the population of the city is 
consuming the standard daily ration, because that is the 
ration for an adult in vigorous, active life, it is evident 
that milk constitutes a much larger percentage of the food 
consumed by the people of New York. It is of still more 
importance because it is almost the entire food of young 
children, and is a large part of the diet of the child up to 
ten years of age, and frequently beyond. In addition, it is 
the chief source of nourishment of invalids and tlie aged, — 
in fact, of any person whose state of health is such that he 
needs an easily digested, liighly nutritious food. AYithout it 
a large number of the sick and invalid a\'ou1(1 undoul)tedly 
perish. It is probably true that an adulterated and im- 
properly handled milk supply will produce more suffering, 
sickness, and death tlian has resulted from the adulteration 
of all other foods combined. There is no other food product 
the condition of Avhich produces such a marked effect on 
the death rate of gf community. The great reduction in the 

33 



34 PUEE FOODS 

death rate of young children in American cities during 
recent years is well known to be due to the great advance 
made in our knowledge of the composition and methods of 
transportation and preservation of milk. 

Constituents of milk. Among common foods milk prob- 
ably approaches nearest the ideal food. It contains all the 
important constituents of a complete food, — protein, fats, 
carbohydrates, and mineral matter. When milk is allowed 
to stand quietly for some time, the fat rises to the top and 
is removed in the form of cream, from which the fat is sep- 
arated in a still purer form as butter. When the skim milk 
sours, the protein, known as casein, separates as curd. The 
various kinds of cheese contain nearly all of the protein of 
the milk as well as more or less of the fat. When the curd 
has been removed, there remains a somewhat sweetish liquid 
known as whey. This contains the sugar and mineral mat- 
ter of the milk. By boiling the whey until a great deal of 
the water has been expelled, and inserting strings or sticks 
of wood, the sugar crystallizes out and is broken up or 
powdered, to be sold as milk sugar. The remaining liquid 
contains most of the mineral matter. By boiling until the 
water is entirely volatilized a solid remains, which can be 
heated to redness without being entirely burned up. This 
residue, which is incombustible, is the mineral matter or ash 
of the milk. Cow's milk, which is the milk most largely used, 
varies considerably in composition, depending on the season, 
breed, age, method of feeding, etc., of the animal. The com- 
position of the milk of a mixed herd is much more constant, 
the figures given in Table VIII referring to such milk. 

The largest constituent is water. The solid constituents 
are not present in the proportion given for the standard 
adult ration, the protein being present in much larger pro- 
portion, so that it approaches more nearly the ration given 



MILK 



35 



for children, who need more protein for the growing tissues. 
When milk is used as a food for the adult, sugar or some 
starchy food such as bread should be eaten with it. In pro- 
tein cow's milk is mucli richer than human milk, while 
human milk is much richer in sugar. 

tablp: VIII 

Composition of Milk 



Constituents 


Cow's milk 


Human milk 


Calories 


325 




Water 


Per cent 

87.3 

12.7 

3.6 

3.8 

4.5 

.1 

.7 


Per cent 
87.4 


Total solids 


12 6 


Fax; 

Protein 


3.78 
2.29 


Milk sugar 


6.21 


Lactic acid 




Ash 


.31 



Eatio of Constituents of Cow's Milk 
Protein 100 : Fat 100 : Carbohydrates 125 



Modified milk. It is evident that if cow's milk is to be 
modified, so as to be used for infants, the amount of 
protein must be reduced. This is done by diluting the 
milk to a considerable extent. This reduces the fat and 
the sugar. These two constituents must then be increased 
by adding cream and milk sugar ; so that in adapting cow's 
milk to the feeding of infants it is diluted and then en- 
riched with cream and milk sugar, and made to correspond 
very closely to human milk, the natural food for the child. 

High protein content. Milk must be classed as a high 
protein food. The amount of protein given in Table VIII, 
3.8 per cent, seems very small, but account must be taken 



36 



PUKE FOODS 



of the fact that there is present in the milk but 12.7 per 
cent of solids, so that nearly one third of this solid matter 
is protein. Meats and fish are the only foods which exceed 
milk in the amount of protein present. Two and a half 
quarts of milk contain as much protein matter as a pound 
of meat, and in addition the milk contains sugar and fat. 
As a food two and a half quarts of milk are worth a great 
deal more than a pound of meat. If one could live on milk 
alone, less than four quarts a day would suffice, and at 
8 cents per quart, it would cost 32 cents per day. Com- 
pared with other high protein foods, this is a very low cost, 
as may be seen from an inspection of Table VI. From the 
following table it may be seen that milk alone is a poorly 
balanced food, with an excess of protein, but that the addi- 
tion of bread and butter improves tlie ration and also reduces 

the cost. 

TABLE IX 

Daily Ration of ]\Iilk 







Cost 


Protein 


Fats 


Carbo- 
hydrates 


Ash 


Calories 


4 quarts .... 


Ccnls 
32 


133 


(In (Ills 
120 


(innns 
157 


(wrams 
24 


2920 



Daily R 


ATION 


OF BlJEAD, BUTTEH, ANT 


Milk 




Milk, 2 qt. . . . 
Bread, li loaves . 
Butter, 1 oz . . . 


16 
6 

2 


60 
50 


63 

5 

•30 


78 ■ 
257 


12 
5 


1460 
1355 

225 


TOTAI 


24 


116 


08 


335 


17 


3040 



A staple food. Milk is classed as a " staple food," because 
it is one which can be consumed continually by a very 
large number of human beings without detriment or par- 
ticular dislike. Only when the adult has been compelled 



MILK 



37 



to live oil milk exclusively for a considerable period does 
he absolutely lose his desire for and enjoyment of milk. 

Variations in composition of milk. The figures given rep- 
resent the average composition of milk. The natural varia- 
tions are quite large. The total solids may vary from 9 
to 17 per cent; that is, one milk may be nearly twice as 
rich as another, the corresponding amounts of water being 
91 and 83 per cent. The fat may vary frcmi 1.67 to 6.4 
per cent, the milk sugar from 2 to 6 per cent, the protein 
from 2 to over 6 per cent, and the ash from .35 to 1.2 per 
cent. On account of these large variations in the composi- 
tion of milk, consumers would be defrauded unless its sale 
were regulated by law. A minimum of 12 to 13 per cent 
of total solids and 3 to 3.V per cent of fat is usually required. 
If the milk contains less than these amounts, for whatever 
cause, it is considered adulterated, so that its sale is illegal. 

Variations in New York City milk. The following table 
shows the variation in percentage of fat in milk sold in 
New York City : 

TABLE X 
Percentage of Fat in ALlk sold in New York City 







Per cent 


Per cent 


Per cent 


Milk Co. No. 1 . 


. 8^, bottled .... 


3.8 






Milk Co. No. 2 . 


. 8^, bottled .... 


3.8 


3.8 


3.6 


Milk Co. No. 3 . 


. 8,0, bottled .... 


3.4 


3.6 


3.5 


Milk Co. No. 3 . 


. 1 5^, bottled (certified) 




4.8 




• Milk Co. No. 4 . 


. 8f, bottled .... 




3.3 




Milk Co. No. 5 . 


. 8^, bottled .... 




3 


2.5 




()/, in cans .... 


3.2 


3.2 


3.1 



The fat varies much more than the other constituents of 
milk, the protein, milk sugar, and ash remaining quite 
constant. The variation in the milk of Dairy Company 



38 



PURE FOODS 



No. 2 occurred within a few days. The milk of Dairy 
Company No. 5, containing only 2.5 per cent fat, was 
below the legal standard, and whether it was watered or 
whether the cows produced such very thin milk, still its 
sale was illegal, and the company selling it was subject to 
a fine. The 6-cent milk is low hi fat also, but just above 
the legal standard. 

Cream. The fat of milk is removed and sold separately 
as cream. It may be separated from the milk in two ways, — 
either by allowing it to rise and skimming it from the top 
of the milk, or by means of mechanical separators, which 
separate the fat very completely from the fresh whole milk. 
We have, then, two kinds of cream, the '' separator " cream 
and the " light " cream. The following table shows their 
composition : 

TABLE XI 







Fat 


other solids 


Water 


Separator cream . . 
Light cream . . . 


Per cent 
38-46 (av. 42) 
8.6-2L6 (av. 13.9) 


Per cent 
6.3 
8.25 


Per cent 
51.7 

77.85 





Comparative cost. The comparative cost of milk, cream, 
and butter, based on the calorific values, is given in the 
following table : 

TABLE XII 
Comparative Cost of Milk, Cream, and Butter 





Cost 


Calories 


Cost of 
1000 calories 


Cream, i pt 

Milk, 1 qt 

Butter, 1 lb 


Cents 
12 

35 


1044 

730 

3605 


Cents 

11.49 

10.96 

9.71 



MILK 39 

Thus we find that cream is the most expensive food of 
this kind that we can buy, milk is the next, and butter is 
the cheapest. 

Skim milk. After the cream has been separated, there 
remains skim milk, which contams nearly the same amount 
of protein, milk sugar, and ash as the sweet milk, while 
only a trace of fat remams. In New York and other cities 
it is illegal to sell skim milk. This is unfortunate, because 
skim milk is an excellent food. It lacks, of course, the 
fat, but contains protein, carbohydrates, and ash, which 
make it a valuable food which could be sold at a fairly 
low price. The danger is that it would be sold as whole 
milk, so that the public would be deceived. If the golden 
rule were observed and every one were honest, unques- 
tionably we should get along better. If every one Avould 
sell skim milk as skim milk, its sale would undoubtedly be 
allowed, and this cheap food product would be available. 
It is sold, however, but not as skim milk. Most of it is sold 
as buttermilk. The buttermilk is prepared by adding to 
the sweet skim milk a pure culture of the bacteria which 
produce lactic acid, and as these bacteria grow the milk 
curdles. Some sweet whole milk is usually added and the 
mixture churned in order to obtain a product resembling 
the buttermilk obtained in the creameries. 

Evaporated milk. The skim milk is also evaporated 
and reduced to a powder, which is known as evaporated 
milk. It contains all the solids of the skim milk, the water 
only having evaporated. It is being used more and more 
by the wholesale food houses, who mix it with flour in 
preparing the special self-raismg flours which are used for 
making pancakes and similar foods. It is more convenient 
to have the milk in this form mixed with the flour, and 
is probably somewliat cheaper than using fresh milk. 



40 PUllE FOODS 

Casein. The casein is also separated from the milk and 
powdered, so that it may be added to other foods, in order 
to increase the proportion of protein. A less pure casein is 
used for other purposes. A cold-water paint is made from 
such casein. Casein will dissolve in water, and, if spread 
out like paint, the solution will dry and form a hard lilm. 
By mixing pigments w^ith it, paints of various colors are 
obtained that will dissolve in water. Where a surface is not 
exposed to dampness, this water paint is quickly applied 
and is convenient. 

EXPERIMENTS 

8. Constituents of milk. Place about 25 cciii. of milk in a porcelain 
evaporating dish and heat on the water bath until dry. The residue 
consists of the fat, casein, sugar, and mineral matter of the milk. 
Add a few cubic centimeters of ether and stir the solid residue with 
a glass rod so as to dissolve the fat. Pour the clear ether solution 
on a watch crystal and allow the ether to evaporate. The residue is 
the butter fat of the milk. By repeating tlie extractiou with ether 
all of the fat may be removed from the milk residue. 

9. Casein and milk sugar. Heat about 200 ccm. of skim milk to 
90° F. and add a few drops of rennet or a few cubic centimeters of 
acetic acid, and allow to stand in a warm place until the milk is 
curdled. The curd is the casein or protein of the milk, and may be 
separated from the whey by filtering through cheesecloth. Make 
the whey slightly alkaline by adding limewater and testing with 
red litmus paper until the paper has turned blue. Evaporate to 
about half the bulk, or until the albumen has been precipitated. 

Filter and again evaporate to about one sixth the bulk. Cool, add 
an equal volume of methyl or wood alcohol, and allow to stand for 
several hours or until a crystalline precipitate is formed. This is 
milk sugar. Filter it off and dry. 

10. Test for borax. Test the milk for borax or boric acid in the 
following manner : 25 ccm. of milk is placed in a porcelain dish, 
a little limewater added, and the whole evaporated to dryness. Pleat 
the dish to redness with the Bunsen burner. The milk residue 



MILK 41 

decomposes and burns. On continued heating, the charcoal burns and 
leaves a white residue. This is the ash or mineral matter in the milk, 
plus the lime which was added. If borax or boric acid had been added 
to the milk as a preservative, it would be present in this residue. 

The preservative may be tested for as follows : Dissolve the resi- 
due in a few drops of hydrochloric acid and moisten a strip of tur- 
meric paper in the solution. Dry the paper, being careful not to heat 
it above 100° C. The development of a bright red color indicates the 
presence of borax or boric acid. The red color is changed to a dark 
green by a drop of ammonia. If a large amount of preservative is 
present, the milk may be tested directly after adding a few drops of 
hydrochloric acid. 

The test may also be carried out in the following simple manner: 
Acidify the milk with a few drops of hydrochloric acid and hang a 
strip of turmeric paper so that the lower edge is moistened with the 
milk. After six or eight hours a cherry-red color will appear at the 
border of the moist portion if boric acid is present. 

In order to become familiar with the delicacy of the test, dissolve 
1 gm. of borax in 100 ccm. of pure milk. Dilute this solution by 
adding 10 ccm. to 90 ccm. of pure milk. Repeat the dilution, using 
10 ccm. of the last solution and 90 ccm. of pure milk. In this 
manner samples of milk will be obtained having 1 jiart of borax 
in 100, 1000, and 10,000 parts of milk. Test these samples of milk 
in the manner indicated and observe the delicacy of the test. 
Also allow the milk to stand several days in order to observe the 
preservative action. 

11. Test for formaldehyde. Test milk for formaldehyde in the fol- 
lowing manner : Place 10 ccm. of the milk in a test tube and pour 
carefully down the side of the inclined tube 5 ccm. of concentrated 
commercial sulphuric or pure sulphuric acid to which a little ferric 
chloride has been added. A violet coloration is produced at the 
junction of the two liquids if formaldehyde is present. 

Also make the test in the following manner : 15 ccm. of the milk 
is placed in a small casserole or other suitable dish. Add an equal 
volume of commercial hydrochloric acid or pure acid to which a little 
ferric chloride has been added. The mixture is slowly heated to the 
boiling point. It is continually stirred or agitated to avoid charring, 
as well as the formation of curd. A violet coloration is produced 
if formaldehyde is present. In this experiment as well as in the test 



42 PURE FOODS 

for borax it is very important that the test be carried out by the 
beginner on samples of milk containing known quantities of the 
preservative. Samples of milk containing 1 part of formaldehyde 
in 1000, 10,000, and 50,000 should be prepared. For this purpose the 
commercial 40 per cent formaldehyde solution may be used. 5 ccm. 
is diluted with water to 20 ccm., and 1 ccm. of this solution is added 
to 99 ccm. of pure milk. On diluting 10 ccm. of this milk with 90 
ccm. of inire milk, and again diluting 20 ccm. with 80 ccm. of pure 
milk, samples are obtained containing 1 part of formaldehyde in 
1000, 10,000, and 50,000 of milk. These samples should be tested 
and then set aside to observe the keeping qualities. 



CHAPTER V 



BACTERIA IN MILK 



Bacteria. Except under very unusual conditions, milk 
invariably contains another constituent, namely bacteria. 
These are minute, microscopic, single-celled organisms. 




fV 



i{^ 



^0] 




" £ K 



t 






i^ 



10 



11 



CP o 
o OlP 



12 



6 







13 






itr 



14 



Fig. 3. A Variety of Bacteria likely to be found in Milk ^ 

1 and 2, typhoid bacillus (Pfeifer) ; 3, pus and pus cocci ; 4, B. Di/senterie 
{Shiga?"); 5, Proteus vulgaris; 6, Clostridiiun hutyricus ; 7, 9, 10, 11, types 
of common lactic bacteria (Conn); 8, a coccus without influence on milk 
{Conn) ; 12, 13, 14, three bacilli producing slimy milk (12, Marshall ; 13 
and 14, Conn) 

which in a favorable environment flourish and multiply 
with enormous rapidity. They vary in shape from circular 
to oval or elongated rodlike bodies. They are capable of 
more or less motion when in liquids, sometimes having a 



i Illustration reproduced from Conn's "Bacteria in Milk and its Products." 

43 



44 PURE FOODS 

number of hairlike flagella which vibrate and propel the 
bacteria. Although so small that they are visible only 
through the microscope, they are very important factors in 
human life. Many of man's most violent and fatal diseases 
are produced by bacteria. A great many very important 
chemical transformations are also brought about by these 
organisms. All of the enormous quantities of alcohol man- 
ufactured every year are produced by the yeast ferments. 
Most of our soils would be arid and unproductive without 
the activity of bacteria. The various processes of decay 
are all brought about by their action. 

The food of bacteria. These minute organisms are nour- 
ished in a manner very similar to that of human beings ; that 
is, the food which they consume is eliminated only after it 
has been transformed into some other chemical compound. 
During this transformation the energy necessary for the 
life of the bacteria is liberated. A given bacterium always 
transforms its food into a definite chemical compound. It 
is therefore possible, by selecting the proper bacterium, to 
transform the starch of any of the grains into alcohol, and 
on this fact is founded the enormous industries manufac- 
turing fermented alcoholic beverages and pure alcohol. By 
using another organism the alcohol may be transformed 
into acetic acid, so that vinegar is produced. Generally the 
food required by bacteria is some form of organic matter, 
which must be in solution or at least quite moist. When 
bacteria which can flourish in the human body and live on 
such organic matter as is present in the .tissues of the body 
gain entrance, disease usually results because the tissues 
are being destroyed. Such bacteria are called disease bac- 
teria, such as typhoid, scarlet fever, etc. Most bacteria can- 
not live under these conditions, but flourish on dead matter 
outside of living bodies and are therefore quite harmless. 



BACTEiUA IN MILK 



45 



Bacteria flourish in milk. The composition of milk is 
such that many bacteria flourish and grow very rapidly 
after gaining entrance. Indeed, few or any other foods offer 
such favorable conditions for their growth. This is largely 
because milk is a liquid containing a variety of food mate- 
rial ill solution. Bacteria 
are so widely distributed, 
being always present in 
the air, water, dust, and 
on the surface of all 
ordinary utensils, that 
they very rapidly gain 
entrance to milk, even 
though considerable care 
is exercised to exclude 
them. By exercising the 
most extraordinary pre- 
cautions it is possible to 
draw from healthy cows 
milk which contains no 
bacteria, so that they 
cannot be said to be a 
natural constituent of 
cow's milk. As it has 
not yet been found prac- 
ticable to draw milk in 
this manner nor to eliminate the bacteria after milking, it 
may be said that bacteria are a normal constituent of milk 
as consumed by human beings. 

Action of bacteria on milk. It is very important to learn 
the character of the bacteria which are found in milk, and 
their effect upon its properties. If they are absolutely ex- 
cluded, it is found that milk does not become sour, but 




Fig. 4. 01d-8t,yle Barn 

Dirty and unsanitary. Particles of dust 
contain thousands of bacteria 



46 PUEE FOODS 

remains sweet for an indefinite period. The souring of milk 
is due to the activities of the so-called lactic-acid bacteria. 
They convert the milk sugar into lactic acid, which causes 
the milk to curdle and gives it a sour taste. As no other 
bacteria can grow so rapidly in milk as this organism, 
they soon far outstrip any others which may have gained 
entrance, and become the predominating organism. A pint 
of sour milk would contain about 20,000,000,000 of these 
minute cells. While such milk is injurious to infants, it 
can be consumed in large quantities by children and adults 
without any ill effects, while there is some evidence that 
at times its use is beneficial. The nutritive value of sour 
milk is very nearly equal to that of sweet milk. 

Tuberculosis transmitted by milk. A great variety of 
other bacteria are also generally found in ordinary milk. 
Some of these are present because the cow is diseased. A 
number of diseases may in this manner be transmitted from 
cattle to man. This is especially true of tuberculosis, which 
has become prevalent to an alarming extent in dairy cattle 
in spite of persistent efforts to check it. Because of the 
almost equal prevalence of the same disease among human 
beings, and the slowness with which it develops after enter- 
ing the human system, it has been found impossible to 
determine to how great an extent the prevalence of the 
disease is to be attributed to an infected milk supply. 
It seems to be well established, however, that the bacteria 
of this disease may at any time be present in our ordinary 
supplies of milk and be transmitted to human beings. 

Other diseases transmitted by milk. A number of other 
diseases, such as diphtheria, typhoid, and scarlet fever, as 
well as dysentery and intestinal diseases, may also be trans- 
mitted by means of milk. Measles and smallpox are also 
believed by many to have been carried by infected milk. The 



BACTERIA IN MILK 



47 



bacteria producing these diseases generally gain entrance to 
the milk from infected persons who handle it at the dairy 
or during its transportation to the consumer. The typhoid 
bacteria may also be introduced from the water used to 
wash cans or other milking utensils. 

Production of pure milk. The requirements, therefore, 
which must be met in producing and delivering a pure 




Fig. 5. Model Stalls 
Plenty of light, and cement floor kept scrupulously clean 

and wholesome supply of milk are the exclusion of disease 
bacteria and the lessening of the activity of lactic-acid bac- 
teria so that the milk shall reach the consumer before it be- 
comes sour. The great concentration of population around 
our large cities has very materially increased the difficulties 
to be overcome by our dairymen. The milk delivered in 
New York City, for mstance, is twenty-four to thirty-six 
hours old. It must be delivered in such condition that it 
will remain sweet at least twenty-four hours longer. The 



48 PURE FOODS - 

production of such a milk supply requires great care at the 
dairy to prevent the entrance of bacteria. The greatest 
cleanliness must be observed with reference to the milking 
rooms, the milking utensils, the cattle, and the dairymen. 
As dust generally carries bacteria in great numbers, it must 
be excluded so far as possible. Plenty of light and air must 
be admitted. In the better class of dairies a veterinary 
surgeon examines the cattle at frequent intervals to ascer- 
tain if they are diseased in any way, and especially in order 
to make the tuberculin test by which it is possible to ascer- 
tain if a cow has contracted tuberculosis in any form. The 
water used to wash milking utensils is tested to insure 
its purity. Dairymen having contagious diseases are not 
allowed to remain at the dairy. To guard against con- 
tamination in transit the milk at the dairy is often put in 
sterilized bottles closed with sterilized caps. Some forty 
rules of this kind have been compiled by a large milk com- 
pany for its dairies, and are enforced by an elaborate system 
of inspectors. 

Certified milk. When every precaution of this kind is 
taken to exclude disease bacteria, and the entire process is 
supervised by a medical association, the product is called 
certified milk and is sold at a much higher price than 
ordinary milk. The only test which -can be applied to as- 
certain if a pure product has been produced, is to make a 
count of the number of bacteria present per cubic centi- 
meter. A limit of about 15,000 is usually established. 
While there is no absolute certainty that some of the bac- 
teria present may not be those producing disease, expe- 
rience proves that this is very rarely the case, so that- 
certified milk may be considered by far the purest milk 
sold. Ijecause of its high cost it is generally used only 
by invalids and children. 



BACTERIA IN MILK 



49 



The use of preservatives" in milk. A number of methods 
have been devised for rendermg milk, produced under or- 
dinary conditions, safe and capable of remaining sweet for 
the necessary length of time. A number of chemical com- 
pounds, known as preservatives, have been found which 
will prevent milk from souring if added in very minute 




Fig. 6. Model Milkino- Room 



quantities. As this method has commonly been condemned 
by health authorities, it has not come into general use. In 
most cities dealers selling such milk are subject to a 
heavy fine. 

Sterilized milk. Heating the milk to a sufficiently high 
temperature has been found to kill the bacteria. If the 
milk is heated to a, temperature considerably above its boil- 
ing point, absolutely all bacteria are killed ; and if properly 



50 



PURE FOODS 



protected from the entrance of bacteria, such milk will remain 
sweet indefinitely. It is then known as sterilized milk. It is 
not, however, a suitable food for invalids and children, the 
high temperature having materially changed its properties. 




Fig. 7. Steam Sterilizer 

The milk bottles are loaded on small cars which are run into the sterilizer, 
the door bolted on, and steam introduced 



Pasteurized milk. It has been found that the various 
species of bacteria are not equally susceptible to the in- 
fluence of heat, so that some are killed at a much lower 
temperature than is necessary for others. This difference 
is largely due to the fact that some species of bacteria are 
capable of producing spores which are analogous to the 



BACTERIA IN MILK 



51 



seeds of plants and can resist drought and heat to a con- 
siderable extent. Under favorable conditions of temper- 
ature and moisture these spores are capable of developing 
into bacteria actively growing and multiplying. As the 
disease-producing bacteria which occur in milk do not pro- 
duce spores, they are destroyed at a relatively low temper- 
ature. This fact was discovered by the great bacteriologist 




Fig. 8. Filling Milk Bottles 
Milk reservoir is covered to keep out dust, and bottles are capped immediately 

Pasteur. His name is therefore given to the process of 
heating milk to a temperature just sufficient to destroy 
these bacteria. This is accomplished by heating the milk 
for twenty minutes at 165° F. or 65° C. Such milk is 
called Pasteurized. It still contains a small number of 
living bacteria or their spores, which develop and multiply 
if the milk is allowed to stand at room temperature for a 
day or two. It will remain sweet for a much longer time 
than the unheated milk, and is a perfectly safe article of diet 



52 PURE FOODS 

because the disease bacteria which may have been present 
have been killed. Some of the constituents have under- 
gone slight changes in composition, as is evident from the 
taste which is not identical with that of the unheated milk. 
In this respect certified milk is to be preferred. 

Advantage of Pasteurization. Pasteurization is the only 
method of treating milk to render it safe as a food, which 
has been found commercially feasible. The increased keep- 
ing qualities of the Pasteurized milk compensates for the 
slight expense of heating it. Both the dairy and domestic 
Pasteurization of milk lias been very extensively employed 
in recent years, so that a large proportion of the milk sold 
in our large cities is now Pasteurized. The commercial 
Pasteurization of milk often differs from the scientific 
method of carrying out this process in that the milk is 
kept hot for a much shorter time than twenty minutes. 
While the vitality and virulence of disease bacteria are un- 
doubtedly very much reduced by such a process, it is 
certain that they are not killed. Fortunately the normal 
healthy human being is able to destroy great numbers of 
disease bacteria, but for invalids and very young children 
it is advisable to Pasteurize for twenty minutes. 

Buddeized milk has been considerably used in Europe. 
This process is somewhat similar to Pasteurization, but 
differs in that the temperature employed is somewliat lower 
than 50° C. or 122° F., and that in addition a small amount 
of hydrogen peroxide is added. This compound is similar to 
water, but differs in that it contains more oxygen. It is an 
excellent disinfectant, and when actmg as such it decomposes 
into oxygen and water, leaving no other decomposition prod- 
uct. During the Buddeizing process all the hydrogen per- 
oxide added is decomposed, while the bacteria are destroyed 
quite as completely as during the Pasteurization. 



BACTERIA IN MILK 



53 



Variations in the bacteria content of milk. The following 
table gives the number of bacteria found in milk as sold in 
New York City : 

TABLE Xlir 
Bacteria in Milk sold ix New York City 





Number per cubic centimeter 


Milk Co. No. 1 . 


. 8^, bottled 


342,000 




Milk Co. No. 2 . 


. 8/', bottled 


84,000 


9,500 12,000 42,600 


Milk Co. No. 3 . 


. 8^, bottled 


84,000 


73,500 179,200 


Milk Co. No. 4 . 


. 8^, bottled 


43,000 




Milk Co. No. 5 . 


. 8;^, bottled 


12,000,000 






6^, in bulk 


4,060,000 


39,000,000 53,000,000 



The very considerable variation in number of bacteria 
present in different samples of milk from the same dairy 
is shown by figures given for Milk Co. No. 2 and No. 3. 

These analyses were made in the fall. During the sum- 
mer the number is much greater. This is due to the fact 
that low temperatures hinder the growth of bacteria. The 
average number of bacteria in the milk sold in New York 
City during the cold winter months is about 300,000, while 
during the summer the average is about 2,500,000. Even 
though no specific disease bacteria can be shown to be 
present, it has been found that the consumption, especially 
by children, of milk containing a large number of bacteria 
is harmful and in the case of infants frequently proves 
fatal. Although no legal limit has been placed on the 
number of bacteria which may be present in milk which is 
sold in cities, 500,000 per cubic centimeter has been pro- 
posed as a limit for this purpose. Good milk should con- 
tain a great deal less than this number. Iii order to prevent 
the sale of milk containing an excessive number of bacteria, 
the board of health of the city of New York has for a 



54 PUEE FOODS 

good many years enforced the rule that no milk shall be 
brought into the city which is not at or below 50° F. 

Influence of the milk supply on the death rate of children. 
The influence of the character of the milk supply on the 
death rate of children is shown by the results of experi- 
ments carried out by Dr. William H. Park and Dr. Emmett 
Holt. 

TABLE XIV 

Effect of Milk Supply on Death Rate of Infants under 
One Year of Age during the Three Summer Months 

Kind of milk Per cent 

Milk in bulk (store milk) 20 

Condensed milk 20 

Bottled milk 9 

Straus Station milk (Pasteurized) 3 

Certified milk or breast milk none 

It is apparent that one child in five is sacrificed by using 
a contaminated milk supply. During the nine cool months 
of the year these investigators found that the character of 
the milk used did not affect the death rate of the children, 
undoubtedly because the number of bacteria in all grades 
of milk during this time of year is very low. 

Determination of the number of bacteria. As the whole- 
someness of milk can be judged from the number of bacteria 
present, the determination of this number is very important. 
Fortunately the method of counting bacteria is fairly simple, 
if the proper preparation is made. A measured volume of 
milk is placed on a plate contaming a sterile nutrient me- 
dium, which is composed of meat extract and peptone to 
nourish the growing bacteria, and gelatin or agar-agar to 
make a semisolid medium in which the bacteria will remain 
fixed. Each bacterium multiplies rapidly, forming a colony 



BACTERIA IN MILK b5 

around it, which soon becomes large enough to be visible 
to the eye alone or under only very slight magnification. 
By counting these spots or colonies the number of bac- 
teria originally present in the milk can be ascertained. If 
the number of bacteria present in the milk is large, a 
definite amount of the milk is diluted with a definite 
amount of sterile water and a portion of this solution taken 
for the test. When many colonies are formed on a plate, 
the colonies on only a small portion of the plate are counted 
and the total number estimated. The determination is at 
best only approximate, as under the conditions of incubation 
all of the bacteria do not grow sufficiently to be counted. 
All material and apparatus used must be thoroughly cleaned 
and sterilized by heat so as to kill all organisms present, 
except those in the milk to be tested. 

EXPERIMENT 

12. Bacteria count. Sterilization of apparatus. Clean thoroughly 
100 test tubes and insert firmly a plug of cotton in each test tube. 
Clean the Petri dishes and the 1-ccm. pipettes. Place the pipettes in 
a copper tube having a close-fitting cap, or in a large test tube 
closed with a plug of cotton. Sterilize this apparatus by placing it 
in an air oven heated to 150° C. for one hour. Prepare sterile water 
by nearly filling a 250-ccm. flask with distilled water and boiling 
vigorously for fifteen to twenty minutes. Insert a plug of cotton 
and allow to cool. 

Preparation of nutrient f/elatin. Place 500 gm. of lean beef in a 
large beaker or flask and add 1000 ccm. of distilled water. The meat 
must be as free as possible from fat and chopped fine or run through 
a sausage grinder. Place a piece of new cotton flannel, with the 
wool side up, in a large funnel and cover with a layer of clean cotton 
wadding. Filter the meat infusion through the flannel, squeezing 
out the last portions. It is advisable to place a second smaller funnel 
containing the same filtering medium below the first funnel, so that 
the filtered solution from the first funnel passes through the second, 
thus giving a very clear solution. Allow the solution to flow into 



56 PURE FOODS 

the inner vessel of an agateware double boiler of at least two quarts' 
capacity. This vessel should be weighed empty as well as after receiv- 
ing the meat infusion. Add an amount of AVitte's peptone equal to 
1 per cent of the weight of the infusion, and 10 per cent of the best 
quality of sheet gelatin (gold label). Dissolve the peptone and gelatin 
by stirring with a thermometer and heating the solution, not allow- 
ing the temperature to rise above 60° C. For this purpose the outer 
vessel only of the double boiler is heated with the Bunsen burner, 
the inner vessel being surrounded by the hot water. After the gel- 
atin is dissolved the water in the outer vessel is brought to a boil 
and kept boiling for thirty minutes, the inner vessel being covered. 

Adjusting the acidity. After the boiling has continued for twenty 
minutes withdraw 5 ccm. of the solution with a pipette and place in 
a porcelain dish or casserole. Add 45 ccm. of distilled water and boil 
for one minute over the Bunsen-burner flame. Add 1 ccm. of phenol- 
phthalein solution ^ and titrate while hot (preferably while boiling) 
with N/20 caustic soda.^ Add the soda solution until within a drop 
or two of the end point (a faint pink coloration). Cool by standing 
the dish in cold water, and if a distinct pink color does not develop, 
add the soda solution drop by drop until the end point is reached. 

So much of the acid in the solution must be now neutralized that 
the amount of acid remaining in 1000 gm. will neutralize 10 ccm. of 
normal caustic-soda solution. The calculation of the amount of soda 
to be added is made as follows : If the 5-ccm. portion titrated required 
4i ccm. of the N/20 soda solution, and the weight of the solution is 
950 gm., the entire solution will require 855 ccm. of the N/20 soda, 
or 42.7 ccm. of normal soda. As the acid equivalent to 10 ccm. of 
normal soda solution must be left free, 32.7 ccm. of normal soda 
solution is added. 

To coagulate finely suspended matter so that the solution maybe 
filtered clear, the white of an ei^g is added at this point. The solution 

1 This solution is prepared by dissolving one tenth of a gram of the crystals 
in 100 ccm. of 95 per cent alcohol. 

2 A normal solution of caustic soda contains 40 gm. of sodium hydroxide 
dissolved in enough water to make 1000 ccm. As even the poorest caustic soda 
generally contains about 90 per cent of sodium hydroxide, about 44 gm. 
must be taken. A twentieth normal solution (N/20) is made by diluting 
50 ecm. of the normal solution to 1000 ccm. with distilled water. For accurate 
methods of making these solutions, see the author's textbook on " Quantitative 
Chemical Analysis." 



BACTERIA IX MILK 57 

is cooled to 60°-70° C. V)y immersing the containing vessel in cold 
water, and the white of an egg added with stirring ; it is then heated 
in the donble boiler and finally boiled for two minutes over the 
free flame, with constant stirring. Weigh and add distilled water 
to make up for loss by evaporation. Take out 5 ccni. and titrate with 
N/*20 sodium hydroxide and calculate the acidity as before. If the 
acidity per 1000 gm. is less than 8 ccm. or more than 12 ccm. of nor- 
mal acid, acid or alkali should be added to bring the acidity to the 
standard 1 per cent. Take out another 5-ccm. jwrtion and titrate a 
third time to ascertain if the adjustment of the acidity has been 
correctly carried out. 

Sterilization of the culture medium. Filter the solution again through 
absorbent cotton and cotton flannel, passing the filtrate through 
the filter until clear. The nutrient gelatin must now be measured 
off in 10-ccm. portions into the sterilized test tubes closed with 
cotton plugs. For this purpose a glass tube graduated every 10 ccm. 
is convenient. The cotton plug is removed from a sterilized test 
tube and held between the first and second fingers, and again in- 
serted into the test tube as soon as the 10-ccm. portion of gelatin 
has been added. The gelatin should not be allowed to touch the 
upper portion of the test tube, which is set aside in an upright posi- 
tion to cool. When all of the gelatin has been measured out into 
test tubes, it is sterilized by heating for five minutes in an autoclave 
at 120° C, which is the temperature of steam at 15 iKUinds' pressure. 
The tubes of gelatin must be kept in an ice chest. If the gelatin has 
not been comjtletely sterilized, colonies will make their appearance 
in a few days. 

The gelatin may also be sterilized by heating in steam for twenty 
minutes for three successive days, being kept in the ice chest when 
not being heated. 

Count of bacteria. To make the count of bacteria in water or 
milk, the sample must be taken in a sterilized glass-stoppered bottle. 
It is advisable before sterilization to cover the stopper with tin foil 
to prevent entrance of bacteria with the dust from the air ; 1 ccm. is 
withdrawn ^ with a sterilized pipette and transferred to a sterilized test 
tube and 9 ccm. of sterilized water added. This gives a dilution of 1 
to 10. By diluting this solution in the same manner a dilution of 

1 When bottled milk^is being tested, the bottle is thoroughly shaken, the 
cap removed, and the 1 ccm. portion withdrawn. 



58 



PURE FOODS 



1-100 is obtained. Most samples of milk must be diluted again, 
giving 1-1000. Very impure milks require still another dilution. A 
clean pipette must be used for each dilution. To one of the sterilized 
Petri dishes 1 ccm. of the 1-100 dilution is transferred, and to the 
second dish 1 ccm. of the 1-1000 dilution. Tubes of the nutrient 




Fig. U. Plate Cultures of Bacteria 

Each spot was produced by a single bacteria. The upper plate contains 

sterilized milk, the left-hand plate certified milk, and the right-hand plate 

ordinary milk 



gelatin are melted by placing in warm water, the plug of cotton 
removed, the open end of the test tube sterilized by passing it through 
the flame of a Bunsen burner, and the gelatin poured into the Petri 
dishes. The covers are raised only when pouring in water or gelatin 
so as to prevent the entrance of bacteria from atmospheric dust. The 
milk and nutrient gelatin are mixed by slightly tilting the dish, so 



BACTERIA IN :VIILK 59 

that the contents flow from one side to the other. The dish is then 
placed in a horizontal position in a thermostat or refrigerator kept at 
abont 20° C. After forty-eight hours the number of colonies on the 
plate are counted. If the number is not over 200, the total number 
may be counted. If the number is large, some counting device must 
be employed. This generally consists of a i)late marked off in sections 
or other divisions, in such a manner that the total number may be 
counted ; the average number of colonies per division is then ob- 
tained by counting the numl)er of colonies in several divisions, so 
as to obtain a fair average of the number per division. Small specks 
of dust must not be mistaken for colonies which are circular in 
shape. The count must generally be made with a small magnifying 
lens. When the colonies are small it is sometimes advisable to 
allow the sample to incubate for seventy-two hours. This fact should 
be stated, however, in reporting the analysis. The best results are 
generally obtained by counting the colonies on plates containing 
about 200. 

Preparation of nutrient agar-agar. When this medium is prepared 
the meat is soaked in one half the quantity of water; that is, 500 ccm. 
Fifteen grams of thread agar are dissolved in 500 ccm. of water by 
boiling for one-half hour. The amount of water lost is then restored 
and the infusion allowed to cool to about 60° C. The remaining opera- 
tions are identical with those used in preparing gelatin, except that 
2 per cent of AVitte's peptone is dissolved in the filtered meat in- 
fusion, after which the agar is added to the meat infusion, care 
being taken to keep the temperature below 60° C. 

The samples of milk are plated as described for gelatin. It is 
necessary, however, to heat the agar to a higher temperature in order 
to melt it. It should be cooled to about 40° C. before pouring on the 
plate. The plates are incubated at body temperature (37^°-40° C.) 
for forty-eight hours. The number of colonies obtained is usually 
higher than with gelatin. It is advisable to use porous earthenware 
covers with agar to prevent the spreading of colonies by the conden- 
sation of water. 



CHAPTER VI 

FATS AND OILS 

Importance of fats in the diet. Fats and oils constitute 
one of the most important constituents of our food. From 
one eiglitli to one tliird of the total amount of food ordi- 
narily taken is fat or oil. As the energy derived from this 
class of foods is more than double that obtained from the 
same weight of the other food constituents, it is evident 
that fats and oils furnish fully half tlie energy obtained 
by human beings from their food. This fact has been 
popularly recognized so long that the word '' fat " has be- 
come synonymous with " rich " or '' superabundant." Fats 
also exert a beneficial influence on the digestive process, so 
that a diet without fat is dry and unpalatable. 

Percentage of fats in foods. Fats are very seldom con- 
sumed in the pure state, but are generally combined or 
blended with other foods. A large proportion of foods in 
their natural state contain an appreciable proportion of fat. 
In fact, all of the fats and oils used for food have been 
separated from the other constituents with which they are 
naturally blended. 

Vegetables and fruits contain very little fat. Bread and 
other cereal products and some kinds of fish contain only 
small amounts. For this reason the addition of butter or 
salad oil renders these foods more palatal)le and nutritious. 
Most meats, as well as a great many nuts and other seeds, 
contain a large proportion of fat. The following table gives 
the percentage of fat present in a number of common foods. 

60 



FATS AND OILS 61 

TABLE XV 
Percentage of Fats in Ordinary Foods 

Percent Percent 

Sirloin steak 17 Coconut 50 

Roast beef 28 Chocolate 50 

Leg of lamb 13 Oatmeal 7 

Ham 40 Bread U 

4 

Bacon 04 Vegetables 1 

Salt pork 85 Fruits i 

Cheese 33 Butter . . . .• 85 



Salmon 17 Olive and salad oils .... 100 

Bluefish 1 

Chemical composition of fats. Fats are composed of the 
same chemical elements as carbohydrates ; that is, carbon, 
liydrogen, and oxygen, although the proportion of oxygen 
is very much less than in carbohydrates. For this reason 
more than double the amount of heat or energy is given 
out during their combustion. Fats are also much more 
complex in structure. If an oil is kept at a low temper- 
ature for some time, it separates into two constituents, one 
of which is solid, and the other liquid. The sohd con- 
stituent can be separated by filtration from tlie li(piid fat 
or oil. If the two constituents are allowed to remain 
together and the mixture warmed, the solid melts so that 
the oil resumes its original appearance. Its properties arc 
not quite the same as before, however. It is a Avell-known 
fact that olive oil which has been frozen Avill not make as 
good a salad dressing: as the unfrozen oil. In a similar 
manner a solid fat may be lieated to a point where only a 
portion is converted into an oil. The solid portion may be 
separated by filtration and is known as stearin. Both solid 
fats like tallow, and oils like cottonseed oil, are converted 
on a commercial scale into more desirable products in this 
manner. From the tallow a hard solid (stearin) and an oil is 



62 PURE FOODS 

obtained. By cooling the cottonseed oil, cottonseed stearin 
may be separated out and the remaining oil will remain 
liquid at much lower temperatures Jthan the origmal oil. 

Glycerin and acids found in fats. It is possible to carry 
the decomposition of both the stearin and the oil still 
further. There are a number of methods of carrying out 
this decomposition, but by each there are obtained as in- 
variable constituents both glycerin and one or more of the 
so-called fatty acids. Experiments of this kind show that 
almost all animal and vegetable fats and oils are composed 
of glycerin in combination with one or more of the fatty 
acids, most natural fats and oils containing several acids. 
Some of these acids form fats which are liquid at ordinary 
temperatures, and are therefore called oils, while others 
form solid fats. Oleic acid is the most common of the fatty 
acids which produce oils, while stearic and palmitic acids 
constitute the bulk of solid fats. A fat like lard, which 
melts easily, contains a large proportion of oleic acid, while 
beef and mutton tallow, which melt at a much higher tem- 
perature, contain a large proportion of stearic acid. These 
acids are always combined Avith glycerin in the natural 
state of the fats or oils. An oil does not contain free oleic 
acid. It contains olein, which is the name given to the 
compound formed when oleic acid combines with glycerin. 
Similarly, tallow contains palmatin and stearin ; that is, 
compounds of palmitic and stearic acids with glycerin. The 
percentage of glycerin is quite small, averaging 8 per cent 
for the common fats. 

Decomposition of fats. As the glycerin and the fatty acids 
are not very firmly combined, most fats are quite easily de- 
composed. Heating with steam and action of bacteria or 
of digestive fluids are some of the common ways in which 
fats are decomposed. The characteristic odor emitted when 



FATS AND OILS 



63 



foods are fried with fat of any kind is produced by acrolein, 
a product of the decomposition of glycerin. The disagree- 
able odor of rancid butter is due largely to the liberation 
of one of its fatty acids known as butyric acid, which has 
a very characteristic and disagreeable odor. In the process 
of making soap, fats are decomposed by means of caustic 
soda or potash, commonly known as soda lye or potash lye. 
In this process the fatty acid combines with the soda or 
the potash and forms soap. When this reaction is brought 
about, the fat is said to be saponified. The glycerin is set 
free and may be allowed to remain in the soap, or may be 
separated and purified to be used for pharmaceutical pur- 
poses or in the arts. 

The fatty acids. The following table gives the names 
and chemical formulas of the fatty acids found in ordinary 

TABLE XVI 

Acids found in Fats and Oils 



Name 


Chemical 
formula 


Where found 


Butyric . . . 


C4H8O2 


Butter 




Caproic . . . 


CeHi,03 


Butter, coconut oil 




Caprylic . . . 


Cs^^ie^^ 


Butter, coconut oil 




Capric .... 


C10H.20O., 


Butter, coconut oil 




Laurie .... 


C,,H,,0, 


Coconut oil 




Myristic . . . 


C^^Bc^^O^ 


Coconut oil 




Palmitic . . . 


C1CH3.3O2 


Nearly all oils and fats 




Stearic .... 


C18H36O0 


Nearly all oils and fats 




Aracliidic . . 


C20H40O. 


Peanut oil, coco butter 




Behenic . . . 


C22H44O2 


Oil of ben 




Lignoceric . . 


C24H48O.3 


Peanut 




Oleic .... 


C:8H.340, 


Nearly all oils and fats 




Rapic .... 


C,,U,^(K 


Rape mustard 




Linolic .... 


C18H32O2 


Cottonseed, corn, almond, 


peanut, olive 


Erucic .... 


^APz 


Rape mustard 





64 PUEE FOODS 

fats and oils. The chemical formulas show that they are 
composed of three elements only ; that is, carbon, hydrogen, 
and oxygen, and tliat the amount of oxygen is quite small. 

The flavor of oils. In addition to the fatty acids and 
glycerin, there are present in oils small quantities of other 
chemical compounds which give distinctive flavors or odors. 
Some oils contain constituents which are either poisonous, 
like croton oil, or have a disagreeable taste or smell, and for 
this reason cannot l)e used for human food. Others have 
constituents which possess medicinal properties, such as 
castor oil and cod-liver oil. The oils which do not contain 
deleterious or medicinal constituents may be used as foods. 
The following vegetable oils are of this character: almond 
oil, coconut oil, cottonseed oil, corn oil, hazelnut oil, olive 
oil, peanut oil, rape oil, sesame oil, sunflower oil, and poppy- 
seed oil. All of these oils will not be used to any great 
extent in a given country, as the people will generally use 
most largely the oils which can be most easily produced 
in that country, although taste and cost will influence con- 
sumption. In nutritive value there is very little difference 
between these oils. There seems to be a considerable dif- 
ference in digestibility, which is apparently dependent on 
the fatty acids which constitute the oil. The oils most 
largely used in the United States for food are olive and 
cottonseed. 

Coconut oil. This oil resembles butter fat more than any 
other natural fat or oil, and has therefore been largely used 
in making artificial butter. It is made from the ordinary 
coconut by pressing the flesh until the oil flows out. 

Cottonseed oil. This oil is most largely used for food 
purposes in the ITnited States, and has also displaced the use 
of other oils to a great extent in Europe. The enormous 
amount of 3,200,000 barrels containing 50 gallons each 



FATS AND OILS 



65 



are produced yearly. Between 2,000,000 and 2,500,000 
barrels, or 125,000,000 gallons, of this amount are used 
for food. If equally divided, this would give each man, 
woman, and child in the United States about a gallon 
and a half, which is therefore the average per capita 
amount of this oil consumed each year by the people of 
the United States. The following table gives the purposes 
for which the cottonseed oil is used : 

TABLE XVII 
Consumption of Cottonskkd Oil for the Ykar 1005 



Salad oil .... 
Cooking and baking 
Compomid lard . . 
Oleomargarine . . 
Packing sardines . 
Soap making . . . 
Other purposes . . 



Doinestic 



Jiamls 

280,000 

170,000 

1,000,000 

10,000 

50,000 

450,000 

145.000 



Foreign 



Barrels 
360,000 

1(),000 
100,000 
250,000 

30,000 
200,000 

44,000 



The oil press. The process of extracting the oil from the 
cottonseed and refining it until it is suitable for food is 
quite complicated. The cotton gin, which separates the 
seed from the fiber, to be used as cotton, leaves a consid- 
erable amount of short fiber known as " linters." In the 
oil mill the linters are first removed, after which the seeds 
are chopped up by rapidly revolving knives and passed 
over shaking screens, which shake out the meats, the hulls 
being passed on to tlie hull pile. The meats containing 
from 30 to 36 per cent of oil are first passed between 
heavy rolls and then cooked in steam-jacketed kettles and 
pressed in hydraulic presses between camel's-hair press 



66 PURE FOODS 

cloths. About 85 per cent of the oil flows out through 
the press cloth. The cake remaining in the press contains 
about 7 per cent of oil and 38 per cent of protein, and is 
largely used as a cattle food. 

The refining of oil. The crude oil thus obtained must be 
refined. For this purpose it is heated and agitated in large 
tanks with dilute caustic soda, which combines with the 
free fatty acids in the oil and also removes resinous color- 
ing matters. After allowing the impurities to settle, the 
clear yellow oil is drawn off, dried, and filtered. This is 
known as '' Prime Summed Yellow " cottonseed oil. It is 
further refined by filtration through Fuller's earth and 
subjected to a deodorizing process. This oil is sold under 
various brands for cooking purposes. 

Lard substitutes. Large quantities of this oil are used 
for the preparation of ''snowdrift," cottolene, and other 
substitutes for lard. These products are made by melting 
up in the heated oil 15 to 20 per cent of oleostearin. The 
melted fat is then cooled suddenly by passing over artifi- 
cially cooled rolls. It then very closely resembles lard in 
appearance and properties. 

Salad oil is prepared by chilling the highly refined cotton- 
seed oil until the '' cottonseed stearin " crystallizes out. 
This so-called '' stearin " is, in fact, palmitin. The oil is 
pressed out of this semisolid mass. Cottonseed oil is used 
very largely for frying, since it will stand a higher tem- 
perature without smokhig than lard or butter. Large 
quantities are also used in making artificial butter. 

Olive oil. This is the most highly prized oil for table 
use. This preference is largely due to its very agreeable 
flavor. It has been used as a food from the very earliest 
times of which we have any historic record. It is no more 
nutritious than the other edible oils. It is about five times 



FATS AND OILS 67 

as expensive, however, as cottonseed oil. On account of 
its high price it has been very largely adulterated by the 
admixture or substitution of cheaper oils. If not more 
than 20 to 30 per cent of a foreign oil is present, it is 
almost impossible to distinguish by taste between the pure 
and the adulterated oil. In the United States cottonseed 
oil has been most largely used as the adulterant, while 
in Europe sesame and peanut oils have been largely used, 
while castor oil, lard oil, fish oil, and even petroleum have 
been found as adulterants. Olive oil contains olein and 
palmitin, but very little stearin. From 3 to 20 per cent 
of palmitin is present. 

Various grades of olive oil. The greatest care is taken in 
the preparation of olive oil. The olives must be hand picked. 
If they are shaken down and bruised, the oil is not of so 
fine a flavor as when made from fruit whose flesh is entirely 
unbroken. The olives should be cold-pressed to produce 
tlie finest oil, which is called '' virgin oil." If the olives 
are heated, the oil begins to decompose so that some of 
the acid is separated from the glycerin, which injures the 
flavor. If perfect olives are cold-pressed, a perfectly neutral 
oil is produced. The residue from the first cold-pressing 
is heated and again pressed, thus producing an additional 
quantity of oil, which is of inferior quality to the virgin 
oil. This oil may be refined by a process similar to that 
used for cottonseed oil, and is then suitable for use as a 
food, but it is not of so fine a quality as the virghi oil, which 
requires little or no refining. A third quality of oil may 
be obtained by treating the residue from the hot presses 
with carbon disulphide or petroleum ether. These liquids 
dissolve the oil and are then distilled off to be used again. 
The oil obtained in this manner should not be used as a 
food, but is suitable for soap making. If too great pressure 



68 PURE FOODS 

is used in obtaining olive oil, the hard kernel of the fruit is 
crushed and an oil pressed out of the kernel which is similar 
to the oil from the flesh of the fruit but distinctly inferior. 
Other food oils. By similar processes the oil is pressed 
out of various seeds and nuts, such as hazelnut, peanut, 
rapeseed, sesame, sunflower seeds, etc. Some of these oils 
are very palatable and easily digested. Their nutritive 
value is very nearly the same as that of the cottonseed 
and olive oil. The preference for one or the other of these 
oils is largely a matter of flavor. 

EXPERIMENTS 

13. Production of stearin. Place a sample of cottonseed or olive 
oil ill ice and salt. For this purpose the oil may be i)laced in a bottle 
or test tube. When thoroughly cooled, a white solid will separate 
out. This is the so-called cottonseed-oil or olive-oil stearin. It 
may be separated from the liquid portion by squeezing through 
cloth of suitable fineness. If allowed to become warm, the stearin 
again goes into solution in the oil. 

14. Determination of acidity. As the glycerin is not very firmly 
combined with the fatty acid, the latter is set free when the fat or 
oil is heated and l)ecomes rancid, or even when allowed to stand for 
some time. The amount of free acid may therefore be taken as an 
index of the method of production or refinement, age or condition 
of the fat or oil, the best oils being nearly neutral. 

The determination is carried out as follows : From 1 to 10 gm. 
of the fat or oil, depending upon the amount of fatty acid present, 
are weighed out and transferred to a small flask. The fat is dis- 
solved in 50 ccm. of neutral alcohol or the same quantity of a 
mixtnre of equal parts of alcohol and ether, if the fat does not 
dissolve in alcohol alone. One drop of phenolphthalein is added and 
then fifth-normal caustic soda^ introduced drop by drop from a 

1 For the preparation of this solution see p. 190. More accurate results 
may be obtained by the use of an alcoholic solution of caustic potash. For 
the preparation of this solution see the author's text on "Quantitative 
Chemical Analysis," 4th ed., p. 437. 



FATS AND OILS 69 

burette with constant and vigorous shaking until a pink color is 
produced. The first appearance of the pink color is taken as the 
end point. It may fade on standing a few minutes, but this is due 
to saponification of the neutral glycerides by the excess of alkali. 

The result is expressed in per cent of oleic acid. One ccm. fifth- 
normal alkali is equal to 0.0561: gm. of oleic acid. If 3 ccm. of 
the alkali is required to titrate the free acid in 2 gm. of fat, the 

/0.0564 X 3 X 100 \ 

percentage of free acid is 8.I(J ( = 8.1() I. 

When carrying out this determination on butter, the fat must be 
melted at the lowest possible temperature and the water and casein 
allowed to settle out. The clear fat is drawn off and used in making 
the test for acidity. If borax or boric acid has been added as a 
preservative, it will be present in the water, which may be tested for 
the preservative in the numner given on page II. 

15. Soap making. In the process of making soap the fatty acids 
are separated from the glycerin by boiling with caustic soda or potash, 
the soap being the compound formed by the imion of the alkali with 
the fatty acid. This process may be carried out as follows : 15 gm. 
of solid caustic soda are dissolved in 120 ccm. of water. One half 
of the solution is poured into a suitable vessel, an equal volume of 
water and 50 gm. of tallow, cottonseed, castor, or other oil added. 
The mixture is brought to a boil and kept l)oiling for about half an 
hour, water being added to replace that lost by evaporation. If tallow 
has been used, it will be necessary to add the remainder of the 
caustic solution and continue the boiling for another hour, finally 
allowing the liquid to become more concentrated. About 20 gm. of 
salt are then added and the solution boiled for a few minutes 
and then allowed to cool. The soap rises to the top and solidifies 
to a hard cake. The glycerin and excess of caustic are present in 
the brine. 

16. Preparation of stearic acid. A portion of the soap made in the 
preceding experiment is dissolved by heating with soft or distilled 
water. If the saponification or conversion of the tallow or oil into 
soap has been complete, a clear solution will l)e obtained. 

Dilute hydrochloric acid is added to this solution until it is de- 
cidedly acid. The liquid will become turbid on account of the sepa- 
ration of the free fatty acids, mainly stearic and oleic. On warming 
the solution and allowing it to stand for some time, the fatty acids 



70 PURE FOODS 

will collect as an oily layer on top of the solution and will solidify 
on cooling. This white fatty substance is what is sold as stearic acid, 
17. Test for cottonseed oil. As cottonseed oil is very cheap as 
well as quite palatable, it is very apt to be used as an adulterant of 
more expensive fats and oils. Fortunately it can be easily tested 
for. For this purpose a solution known as Halphen's reagent is 
used. It is made by dissolving 1 gm. of sulphur in 100 ccm. of 
carbon disulphide and adding an equal volume of amyl alcohol. 
Equal volumes of this reagent and the oil to be tested are mixed in 
a test tube and heated by immersion in boiling water, or, still better, 
boiling saturated brine. After heating for about fifteen minutes a 
red color is developed if cottonseed oil is present. The delicacy of 
the test may be studied by applying it to samples of oil containing 
known amounts of cottonseed oil. For this purpose 10, 20, and 50 
per cent of cottonseed oil may be added to olive, lard, or other suit- 
able oil and the test applied. It will be observed that the depth of the 
color will give some idea of the amount of cottonseed oil present. 



CHAPTER YTT 

BUTTER AND ITS SUBSTITUTES 

Production of butter. Butter is the product obtained by 
a process having for its object the separation of the fat of 
millv in a relatively pure form. The first step in this process 
consists in the production of cream. While milk contains 
only about 31^ per cent of fat, cream may contain as much 
as 40 per cent, the remainder being casein, which is the 
protein of milk and water. The fat is present as minute 
globules, which are surrounded by a layer of casein. These 
globules are so small and light that they float in the whey 
of the milk. When the cream has become acid by the action 
of bacteria, it is subjected to a vigorous agitation known 
as churning, by which the casein is separated from the fat, 
which then unites to form large masses of butter, the 
composition of which is given in the following table : 

TABLE XVIII 
Composition of Butter 

Per cent Per cent 

Eat 80 to 85 average 84 

Water 7 to 16 average 12.8 

Salt 2 to 3 average 2.0 

Sugar 0.3 to 0.5 average 0.4 

Protein 0.6 

Coloring matter 

As is shown by the table, butter is not 100 per cent fat, 
but still contains some water, casein, sugar, and salt as 
ordinarily consumed. 

71 



72 PURE FOODS 

Butter fat. The butter fat could easily be separated in 
pure condition, but it would not be as palatable an article 
of food as the butter to which we are accustomed. The 
fat, however, is the essential constituent of butter. It is 
to obtain this constituent that man so universally and 
commonly uses butter in his daily diet. Butter fat is un- 
doubtedly the most readily digested and easily assimilated 
of this class of foods. It is also more agreeable in flavor 
than any other fat. In chemical composition butter fat is 
similar to the other common vegetable and animal fats and 
oils ; that is, it is composed of glycerin and a number of 
fatty acids of which oleic and palmitic constitute about 71 
per cent. About 20 per cent is composed of volatile fatty 
acids. The peculiar characteristics of butter are undoubt- 
edly due to the presence of these acids. One of these acids 
has taken its name from butter, being called butyric acid. 
The average composition of butter fat is given in the fol- 
lowing table : 

TABLE XIX 
Composition of Buttkk I'at 

Acids Per cent Acids Per cent 

Dioxystearic 1 Laurie 2.57 

Oleic 32.50 Capric 0.32 

Stearic 1.83 Caprylic 0.49 

Palmitic 38.61 Caproic 2.09 

Myristic 9.89 Butyric 5.45 

Glycerin 5.25 per cent 

Constituents of butter. The various constituents of but- 
ter may easily be separated in the following manner: 
A piece of butter is placed in a test tube or other glass 
vessel. It is melted by placing the vessel in warm water 
or by applying other gentle heat and then allowed to stand 
for a few moments. The butter fat forms the clear upper 



BUTTEE AND ITS SUBSTITUTES 73 

yellow layer. Underneath the fat the casern collects as 
a white solid, while at the bottom is formed a colorless, 
watery portion wliich is a solution of the salt and the 
small amount of sugar present in the butter. 

The flavor of butter. Considerable care is necessary to 
produce butter having a perfectly sweet and agreeable 
flavor. While this does not add dhectly to tlie nourishing 
constituents of an article of food, it is of great value in 
inciting the flow of the digestive fluids and promoting good 
digestion, especially in the case of persons of acute sensa- 
tions. Delicacy of flavor also adds very materially to the 
price which may be obtained for an article of food. The 
development of flavor in butter seems to be due entirely 
to bacterial action. By introducing pure cultures of the 
right kind of bacteria into sweet cream, butter of most ex- 
cellent flavor will be obtained. Other bacteria develop 
very disagreeable odors and tastes. By controlling the bac- 
terial content of the cream, the best modern dairies pro- 
duce butter of very uniform and excellent flavor. Much 
butter, however, is still produced by small dairies accord- 
ing to old-fashioned methods by which any bacteria by 
chance present are allowed to act on the cream before it is 
churned. Carelessness in handling both cream and butter 
leads in many cases to the production of butter which is 
far too rancid and disagreeable in flavor to be sold for 
table use. Much of this butter is subjected to a process 
of purification. 

Renovated or process butter, as such a purified product 
is called, has been treated as follows: The poorly made 
butter is first melted in large tanks. By blowing air through 
the melted fat most of the disagreeable odor is removed. 
The casein and brine which are allowed to settle to the 
bottom of the tank contain most of the bacteria producing 



74 PURE FOODS 

the decomposition and disagreeable taste. The clear fat, 
which is now quite sweet, is drawn off and mixed with 
sweet milk and the whole churned. The remainder of the 
process is identical with that of making butter from cream. 
The resulting product has generally a fairly sweet odor and 
taste and finds a ready market. It differs somewhat in com- 
position from that of true butter. While it is a wholesome 
and nutritious article of diet, it is inferior in flavor to good 
butter and is sold at a much lower price. In most states 
its sale is carefully regulated by law, with the intent that 
the purchaser shall clearly understand that he is not buying 
creamery butter. For this purpose the words " renovated 
butter " must be printed on the package and also displayed 
on a conspicuous sign over the article on sale. 

Oleomargarine or butterine. This is the name given to 
butter substitutes m which a portion or all of the butter 
fat has been replaced by a foreign fat. As has been already 
stated, all fats are very similar in composition, and only a 
small portion of the constituents of butter fat differs from 
other ordinary fats and oils. The attempt has therefore 
been made to find a combination of various animal and 
vegetable fats which is similar in composition and proper- 
ties to natural butter fat. The manufacturer is restricted 
to fats and oils which are cheaper than butter fat and can 
be readily obtained. For this and other reasons the attempt 
to make artificial butter has been only partially successful. 
A perfectly wholesome and nutritious product has been 
obtained without, however, having the flavor of butter 
nor its peculiar adaptability to the digestive system, so 
that it can be continually eaten with relish. For this rea- 
son some natural butter is almost invariably mixed with 
the artificial product in order to give it an agreeable taste 
and odor. 



BUTTEE AND ITS SUBSTITUTES 75 

Wholesomeness of oleomargarine. The manufacture of 
oleomargarine is carried on under strict government con- 
trol and inspection so that no unsanitary methods nor un- 
wholesome ingredients are allowed to be used. As the 
ingredients used are wholesome and nutritious articles of 
food, oleomargarine cannot be condemned as a food. The 
opposition to it has arisen from the fact that it has often 




Fig. 10. Wrapping and Packing Butterine for Shipment 

been offered and sold as butter. This practice not only 
defrauds the customer but tends to drive the genuine arti- 
cle out of the market, as it cannot be produced at as low 
a cost as oleomargarine. When sold for what it is and at 
a lower price than butter, oleomargarine undoubtedly ren- 
ders the fat element of human diet available to people who 
could not afford the more expensive butter. While a good 
grade of oleomargarine is a more wholesome and palatable 



76 PURE FOODS 

article of food than a poor grade of butter, the best grades 
of butter have a finer flavor and are more easily assimilated 
than any substitute as yet produced. The keeping qualities 
of good oleomargarine are excellent. Mixtures of oleomar- 
garhie and butter in various proportions are very palatable 
and considerably cheaper than pure butter. 

The practice of coloring butter with vegetable or aniline 
dyes is very general, but if the dye is not a poisonous one, 
there can be little objection to the practice. 

Manufacture of oleomargarine. Both animal and vege- 
table fats and oils are used in the manufacture of oleomar- 
garine. The finest neutral lard is heated to 45° C. for 
some time and then subjected to hydraulic pressure. Most 
of the stearin is removed in this manner and used for other 
purposes, while the oleo oil forms the raw material for the 
manufacture of the artificial butter. The most commonly 
used vegetable oil is cottonseed, which together with oleo 
oil and milk are placed in churning machines which serve 
to beat the oils into minute drops resembling the con- 
dition of the fat in natural butter. In some cases coloring 
matter is added as well as substances which give taste and 
odor similar to butter. Generally a small amount of but- 
ter is also introduced for the same purpose. 

EXPERIMENTS 

18. The foam test for butter. Place a tablespoonful of pure butter, 
renovated or process butter, and oleomargarine in each of three small 
beakers or other suitable vessels. Heat over the Bunsen burner or a 
stove until the samples melt. On continued heating, the butter boils 
quietly, producing considerable foam, while the oleomargarine and 
the renovated butter produce very little foam and sputter and crackle 
violently. 

19. The milk test. Place a tablespoonful of each of the three sam- 
ples used in Experiment 18 in each of three small beakers or small 



BUTTER AND ITS SUBSTITUTES 77 

cups containing a few ounces of sweet milk and warm gently until 
the samples are melted. Place the vessels in cold water, and while 
the fat is still melted, stir vigorously with wooden sticks of con- 
venient size. As the fat hardens, it will be found that the pure and 
renovated butter will make an emulsion with the milk very similar 
to cream, while the oleomargarine will not mix with the milk but 
will solidify into a solid chunk of fat, which will often adhere to 
the stick so that it can be lifted out of the milk. 

As cottonseed oil is frequently used in the manufacture of oleo- 
margarine, the test for this oil by means of Halphen's reagent, as 
given on page 70, is of great assistance in proving the pi'esence of 



CHAPTER VTII 

MEATS 

The importance of meat in the diet. Meats are of impor- 
tance in the Imnian diet on account of their high content of 
protein. The solid portion of the lean of meat is very nearly 
pure protein, containing only very small amounts of fat, 




Fig. 11. A Train of Cattle Cars bringing Stock from the Western 
Plains to Chicago 

carbohydrates, and mineral matter. Tlie average composi- 
tion of lean meat may he given as 25 per cent protein and 
75 per cent water. The presence of protein in the human 
diet is of the highest importance, because the protoplasm 
or living portion of the human system can be built up and 
nourished only by this constituent of our food. If it were 
entirely absent, we should starve to death as certainly as if 
we ate no food at all, although by no means as quickly. 

Substitutes for meat. We are by no means compelled to 
eat meat in order to obtain this valuable constituent of our 



MEATS 



79 



food, because many vegetable foods contain protein in large 
amounts. It seems, however, that the protein of meat is 
much more easily digested and more readily assimilated by 
the tissues than vegetable protein, so that meats are a very 
desirable constituent of the human diet. Most meats as 
ordinarily consumed contain considerable quantities of fat, 
so that when eaten with potatoes, which are composed 









1 


--r-J^mSSSm^^^ -^'-""■^ 








1 


^^^^rl^i^^^H^ 


'***"*»B.^ ij 




^r«t 


-- ^■''- ■C^,..--'.- 


f 




/: 



Fig. 12. A Portion of the Chicago Stockyards 



almost entirely of starch, the combination furnishes all 
constituents of a complete diet. As meats are a relatively 
expensive food, economy as well as good health is attained 
by limiting their consumption to the amount actually neces- 
sary to meet the needs of the system. 

The danger of excessive use of meat. On the other hand, 
serious dangers attend the consumption of meats, especially 
in excessive quantities. This is due to the fact that the 



80 PURE FOODS 

decomposition products of protein are not readily eliminated 
from the system, and give rise to various disorders and 
diseases. The proteins of meat also seem more liable to 
decompose in such a manner as to give rise to highly poison- 
ous substances. The consumption of meat should therefore 
be limited to the amount necessary to build up and repair 
the tissues of the body. As both growth and the breaking 
down of the tissues are very slow processes, the amount of 
protem consumed need not be large. It must not be for- 
gotten that all vegetable foods contain some protein, and 
some of these foods contain a very large percentage of this 
constituent. One half pound of lean meat per day taken 
with other ordinary foods is therefore amply sufficient for 
the average adult. 

Unsanitary meat. Meats may be unwholesome for a 
number of reasons. The animal from which the meat is 
derived may be diseased at the time of slaughter. Such 
diseases are not necessarily communicated to the person 
eating the meat, although in some cases they may be. This 
is true of trichina in pork and tuberculosis in cattle. The 
animal also may not be of the proper age for slaughter. 
The slaughter of very young calves is generally prohibited 
by law, their flesh not being fit to eat. The meat should 
not be eaten if the animal has died a natural death. The 
meat from perfectly liealthy and sound animals may be 
rendered unfit for food by unsanitary methods of slaughter 
and liandling of the meat. 

Inspected meat. As it is almost impossible in many cases 
by an examination of meat or meat products to obtain 
evidence that the animals were unfit for food or that the 
meat was improperly handled, an essential part of any 
effective method of protectmg the public agamst an un- 
wholesome supply is a rigid inspection of the animals before 



MEATS 81 

slaughter, as well as the method of handling the meat until 
it reaches the consumer. Such a system of inspection is 
now mamtained by the national government. 

Characteristics of sound meat. The purchaser may, how- 
ever, in many cases distinguish between wholesome and 
unwholesome meat by an inspection of the article as offered 
for sale. Sound fresh meat should have the following 
characteristics : The color should be neither pale pink nor 
dark purple. In the first case the animal was probably 
diseased ; in the second case it was not slaughtered but 
died a natural death. Fresh meat should be firm and elastic 
to the touch and should hardly moisten the finger. Wet, 
sodden, or flabby meat, which is soft and jellylike to the 
touch, should not be used. Moreover fresh meat sliould 
be almost free from odor. Diseased meat has a sickly dis- 
agreeable odor. On standing a day or two it should grow 
drier, but should not become wet. The following simple 
chemical tests may also be applied in doubtful cases : It 
should be acid toward litmus or other indicator ; that is, it 
should turn blue litmus paper red. If it is neutral or alka- 
line, preservatives such as borax have been used. When 
dried at 100° C. it should not lose more than 70 to 74 per 
cent in Aveight. Unsound meat may lose 80 per cent or 
more. On cooking, it should shrink very little. 

Similarity of various kinds of meat. Although the various 
kinds of meat, such as pork, beef, mutton, etc., differ con- 
siderably in taste and ease of digestion, chemically they are 
so similar that it is quite difficult to identify the ingredients 
of a mixture of these meats if they have been chopped fine 
so that no large pieces remain. 

Refrigeration of meat. The only method of preserving 
fresh meat, which is generally conceded to be unobjection- 
able, is by refrigei'ation. There is some difference of opinion 



82 



PUEE FOODS 



as to how long meat may be kept in this manner without 
deterioration. Some observers report that the meat begins 
to deteriorate after three months, while other investigators 
find no change after as many years. It seems, however, that 
the condition of the meat is affected by the temperature to 
whicli it is exposed and also by the conditions under which 
it is allowed to thaw. To obtam the best results, the meat 




Fig. 13. Meat in Cold Storage 

must be subjected to a temperature low enough to freeze 
it solid; that is, none of its juices should remain liquid. 
This result is obtained with beef by keeping it at a tem- 
perature at or below — 9° C. or 16° F. When such meat is 
thawed, it should be allowed to warm up very slowly, as 
otherwise it will be flabby. This is due to the fact that 
during the process of freezing the juices have been forced 
out of the cells. If warmed up slowly, these juices reenter 
the cells slowly, so that the meat assumes its natural firm 
condition. 



MEATS 



88 



Chemical preservatives. These substances have been used 
quite extensively in preserving meats. Boric, sulphurous, 
and benz(Hc acids have been most generally employed. In 
addition to preserving the meat, sulphurous acid has also 
the property of giving it a bright red color. Saltpeter or 
potassium nitrate has the same effect on the color of the 
meat, but this salt has very little preserving power. Meat 




Fig. 14, Packing Poultry for Shipment 

which contains a chemical preservative will emit no dis- 
agreeable odor, even when it is so old and decomposed that 
without the preservative it would be quite foul. If sulphur- 
ous acid is used, the meat will also retain the bright red 
color of fresh meat. The use of these substances, there- 
fore, renders possible the sale of meat which would other- 
wise be discarded. Such meat is sometimes used for the 
preparation of sausage. The sulphurous acid is introduced 
as sodium or calcium sulphite, ^he red color is sometunes 



84 PUEE FOODS 

restored to decomposed meat by the addition of coal-tar 
dyes, cochineal, or red ocher. 

Objections to the use of preservatives. The treatment of 
meat with coloring matter or preservatives is to be con- 
demned, and the sale of snch meat is illegal. While it is 
possible to find preservatives and coloring matter that are 
not demonstrably unwholesome in the minute amounts that 




Fig. 15. A Roomful ot Lard 

it is necessary to employ, it is obvious that if the meat were 
in good condition, neither preservatives nor coloring matter 
would be necessary. As these substances are added for the 
purposes of deceiving the customer, their use is fraudulent. 
The use of saltpeter or potassium nitrate in corned beef is 
not considered fraudulent, because the meat so treated is 
not injured, and the custom has been long established. 

Gelatin. This is one of the most commonly used of meat 
products. It is a nitrogenous substance, which has the 



MEATS 85 

property of forming a jelly with a very large amount of 
water. Good gelatin will form a jelly with fifty times its 
weight of water. It is extracted from the bones, tendons, 
hides, and hoofs of the slaughtered animals. Tendons, hides, 
hoofs, etc., are first treated with lime to remove hair and 
dissolved mucin. After washing, the gelatin is dissolved 
out by means of hot water. Sulphurous acid is sometimes 
added in order to produce a Aviiite product. After drying 
and powdering, the gelatin is ready for use. It is not pres- 
ent as such in the bones, hides, etc. A substance called 
collagen, very similar to gelatin, is present and is con- 
verted by the hot water into gelatin. Gelatin is a per- 
fectly wholesome article of food if carefully made from 
fresh material. It decomposes very readily and may be con- 
taminated with tetanus and other disease bacteria unless 
the greatest cleanliness is observed during its manufacture. 

EXPERIMENTS 

20. Testing meat for borax. Test samples of meat for )>orax or bo- 
ric acid according to the method given in Experiment 10, p. 40. 
Prepare samples of meat containing borax by sprinkling the powder 
over the snrface of the meat. Use a portion of the sample for mak- 
ing the test for borax, and set aside the other portion for observation 
on the preservative action of the borax, a sample of the nntreated 
meat being placed with the preserved sam[)le. 

21. Testing meats for sulphites. Sulphites are largely used to pre- 
serve and give a bright red color to chopped meats or "Hamburg 
steak." Samples of such meat may be tested as follows : A small 
portion is placed in a small dish or beaker and moistened with 
dilute phosphoric acid and then heated gently. If a large amount of 
sulphite has been added, the sulphur dioxide evolved on heating can 
be detected by the odor, which is that of burning sulphur. 

A much more delicate test consists in exposing a piece of starch- 
iodate paper to the action of the gases and steam arising when 
heating the meat with phosphoric acid. If sulphites are present, the 
paper is turned blue. The starch-iodate paper is prepared by first 



86 



PUEE FOODS 



making thin starch paste. The starch is made into a thin paste with 
cold water, which is dihited hy adding a considerable amount of boil- 
ing water while stirring continually. A few crystals of potassium 
iodate are dissolved in water and added to the starch 2:)aste. Strips 
of filter or other porous paper are then dipped into the solution and 
drained and allowed to dry. This paper should be preserved in well- 
stoppered bottles. 

A still more delicate test for sulphites is carried out as follows : 
40-50 gm. of the meat to be tested is mixed with water and heated 




Fig. 16. Distillation of Sulphurous Acid 



for a few minutes. Ten ccm. of glacial phosphoric acid is added and 
the solid material strained off through a cotton cloth. The solution 
is then placed in the second flask, shown in Fig. 16, and distilled. 
The water in the first flask is brought to a boil. The steam entering 
the second flask heats the solution of the meat. The Bunsen burner 
under the second flask is then lighted and the flame of the Bunsen 
burners regulated so that the meat solution is kept gently agitated 
without any great change in volume. The distillate is received in a 
beaker containing a little bromine water. After about 200 ccm. has 
been distilled over, the bromine is boiled out, a little hydrochloric 



MEATS 87 

acid is added, and then a few drops of a 10 per cent barium chloride 
solution are added to the boiling hot solution. After boiling for some 
time, the solution is set aside to cool and examined carefully for the 
presence of a precipitate. A white precipitate is evidence that a 
sulphite has been added to the meat. A very slight precipitate is 
generally obtained, even from pure meat, because the protein of meat 
contains a small amount of sulphur, part of which is carried over 
during the distillation process. 

Tests should be carried out on samples of pure meat before and 
after the addition of weighed amounts of sulphites. Sodium or cal- 
cium sulphites may be used for this purpose. 

The amount of sulphite which has been added to the meat may 
be accurately determined by weighing the barium sulphate obtained 
in the distillate from a weighed amount of meat. For this purpose 
the precipitate is filtered o£E on an ashless filter paper and washed 
thoroughly with hot water. The wet paper with the precipitate is 
placed in a weighed crucible and the paper burned by gently heating 
the crucible, which is finally strongly heated, cooled, and weighed. 
One gram of barium sulphate is equivalent to 0.2745 gm. of sulphur 
dioxide.! 

1 For detailed instructions for this determination see the author's text- 
book, "Quantitative Chemical Analysis." 



CHAPTER IX 

carbohydrates 

Starch, Sugar, and Sirups 

Importance of carbohydrates in the diet. Wliile gen- 
erally occiiiTing in natural products together with other 
constituents, this important class of foods may be sep- 
arated in a very nearly pure condition, just as fats and 
protein are available without admixture with other food 
constituents. As the human system seems to be able to 
obtain the necessary supply of energy most economically 
from carbohydrates, their preparation as food is very im- 
portant. This consists essentially of two processes: first, 
their separation from other substances Avith which they 
are associated in natural products ; and second, the con- 
verting of insoluble into soluble compounds. Starch is the 
most common insoluble form, while the sugars and sirups, 
lioney, etc. are common illustrations of soluble carbohy- 
drates. Starch is a very large constituent of nearly all 
seeds and grains, such as Avheat, corn, rice, etc., while the 
sugars are present in large quantities in nearly all fruits 
and in the juices of many plants, such as sugar cane, the 
maple tree, etc. 

Necessity of cooking starch. Tlie digestion of starch con- 
sists essentially in its conversion into simple soluble forms. 
In the preparation of food products the starch may be 
subjected to a similar process so as to render it more or 
less soluble. It is then more easily digested. It is very 
essential to start this conversion before starch is eaten, as 



CAEBOHYDPvATES 89 

raw starch is quite indigestible. The process of cooking by 
roasting or boihng renders the starch sufficiently soluble for 
rapid action by the digestive fluids. On the other hand, it is 
not advisable to consume only starch which has been fully 
converted into soluble forms (mainly the sugars), because 
such food is almost immediately taken into the circulation. 




Fig. 17. Steel Tanks for the Storage of Corn 

Each tank will hold 85,000 hushels, or 85 carloads of corn, which is converted 
into starch, glucose, etc. in three days 

At least some food is needed which will dissolve gradually 
and nourish tlie system continuously. A diet containing 
both soluble and insoluble carbohydrates, such as sugar and 
starch, is best suited to meet the needs of the system. 

Natural products containing starch. While a very large 
portion of the starch consumed as food is taken in its natural 
condition in such foods as potatoes, rice, bread, and the 
numerous foods jfrepared from corn, oats, etc., it is found 



90 PURE FOODS 

convenient for many purposes to separate the starch in the 
pure state. Corn and potatoes are the natural products 
which have been most largely used for the manufacture of 
starch. Both of these foods are composed almost entirely 
of starch, the process of manufacture consisting simply in 
the elimination of the other constituents. As corn can be 
produced in abundance and cheaply in the United States, 
it is the source from which most of the American starch is 
made, while for analogous reasons the potato has been used 
in Europe. 

Structure of a grain of corn. An examination of a grain 
of corn will show that it has an outer hard hull or shell 
which protects the grain from injury. If a grain be split 
parallel to the flattened sides, the soft germ can be seen 
imbedded in a mass of starch. When the germ sprouts 
through the action of moisture and warmth, the starch is 
converted into sugars, which dissolve and are absorbed and 
nourish the growing plant. The germ contains a consider- 
able amount of protein and oil, while some protein, known 
as gluten,! is also mixed with the surrounding layers of 
starch. Processes have been developed for separating the 
starch, protein, and oil very completely. 

Separation of the germs. For this purpose the grain is 
first steeped in water containing sulphurous acid. This 
softens the entire grain, loosens the hull from the re- 
mainder of the grain, and dissolves the gluten which serves 
to bind the starch grains together. The soft corn is then 
passed through the so-called '' foose mills," which break the 
grains of corn into coarse particles. It is then mixed with 
water and pumped into the '' germ separators," which are 

iThis gluten is not identical with the gluten of wheat. It is composed of 
two proteins, edestin and zein, while the gluten of wheat is composed of 
glutenin and gliadin. 



CARBOHYDRATES 91 

long, deep, steel tanks. The ground corn suspended in the 
water is delivered into the upper end of these tanks. The 
germs being light, on account of their content of oil, float on 
top and are swept to the lower end by means of strips of 
wood, which are moved slowly over the surface of the liquid 
by means of belts to which they are attached. The starch 
and hulls being heavy drop to 'the bottom and are carried 
away in separate conveyors. In this very simple manner 
the germs which have been left practically intact are sepa- 
rated very completely from the starch and hulls. 

Production of corn oil. By subjecting the germs to pres- 
sure corn oil may be produced, which is used for making 
soap, or, when refined, as a cooking oil ; or it may be con- 
verted into a substitute for rubber. The germs remaining 
in the strong canvas bags of the oil press form what is 
known as '' oil cake." This still contains a small amount 
of oil as well as a large amount of protein and starch and 
some mineral matter. It has been found to be an excellent 
cattle food and is largely used by dairymen to increase the 
yield of milk and butter. 

Manufacture of starch. The starch and hulls Avhich set- 
tle to the bottom of the ''germ separators" are next passed 
over the so-called '' shakers." These consist of frames cov- 
ered with perforated copper, copper gauze, or silk bolting 
cloth. By means of machinery they are kept in constant 
motion, back and forth, which gives the name '' shaker " 
to the apparatus. The finer particles of the starch pass 
through the shaker, Avhile the coarse particles, consisting 
of hulls with some attached starch, are carried over the 
end of the shaker. This material is again ground in bur 
or stone mills, and again passed over shakers in order 
to remove the remainder of the starch from the hulls. 
The starch which has passed through the shakers is held 



92 PURE FOODS 

suspended in water, forming the so-called " starch liquor," 
which is pumped to the starch tables. These are long 
wooden troughs slightly inclined. The starch liquor enters 
the trough at the upper end, and as it flows slowly to the 
lower end the starch settles to the bottom, forming a com- 
pact layer, Avhile the gluten and the water flow out at the 
lower end. The starch is 'then shoveled into conveyors, 
which carry a portion of it to the drying rooms to be 
made up into the various forms of dried starch. A single 
factory produces annually 75,000,000 pounds of starch in 
this manner from corn. 

The conversion of starch into sirup and sugar. While a 
considerable quantity of starch is used in foods, laundry 
work, and many technical processes, a very considerable 
proportion is converted into glucose or corn sirup and 
starch sugar. These substances are chemically very similar 
to starch, differing mainly in that they are soluble and 
sweet, Avhile starch is very hisoluble and almost tasteless. 
They are also inucli more easily digested. When starch is 
to be converted into glucose, or starch sugar, it is sus- 
pended in water and a small amount of hydrochloric acid 
is added. The starch liquor is pumped into closed copper 
tanks, called '' converters," in which it is heated by means 
of steam under pressure. Under these conditions the starch 
undergoes a transformation by which it takes up a small 
amount of water and forms soluble compounds similar to 
sugar, so that the liquor acquires a sweet taste. Because 
the starch combines with water, this process is called hydrol- 
ysis. The compounds produced are mainly clextrme and 
dextrose. The first substance formed is dextrine, which may 
be called a soluble gum and is largely used for mucilage and 
other pastes. The same substance is formed in the crust of 
bread during the process of baking. On further heating 



CARBOHYDRATES 98 

with acid, the dextrine breaks down still further into two 
sugars, maltose and dextrose. On continued heating the 
maltose is also broken down into dextrose, leaving tliis 
product only. The sugars are not the same as ordinary 




Fig. 18. Top of Charcoal Filters 
The sirup Hows into the filter through the curved pipes 

granulated or cane sugar, which is known as sucrose. Dex- 
trose is less sweet than sucrose, so that glucose is only 
about three fifths as sweet as ordinary sugar. If the heat- 
ing of the starch liquor is prolonged, the starcli is converted 
almost completely hito dextrose, which crystallizes out and 
forms what is known as starch sugar or corn sugar. 



94 



PURE F0OJ)S 



Purification of the sirup. After the starch has been con- 
verted into sugars in this manner the liydrocliloric acid is 







-•■■•» 


!^^SVHRBPh|H 



Pig. 19. Body of Charcoal Filter, which is a Steel Tank entirely filled 
with the Sirup and Charcoal 

neutralized with soda asli and converted into sodium chlo- 
ride, which is the main constituent of common salt. Some 



CARBOHYDRATES 



95 



of the impurities in the hquicl separate -out at this stage of 
the process and are removed by filtration through canvas 




Fig. 20. Vacuum Pan for Concentration of the Sirup 
The capacity of the pau is 100 barrels of sirup 

in filter presses. After passing through these presses the 
solution is clear and transparent, but dissolved impurities 
give it a yellow color. To remove these impurities and 



96 PURE FOODS 

decolorize the solution, it is passed into large steel tanks 
filled with bone char. The charcoal or carbon present in 
this material absorbs the impurities and clarifies the solu- 
tion. The same material is used in the same manner for 
clarifying solutions of ordinary sugar, or sucrose. The 
bone char may be used repeatedly, as the impurities arc 
burned out in specially designed kilns. 

Concentration of the sirup. In the next and final step 
in the process the solution is converted into a thick sirup 
by removing the excess of water. Tins is done by boiling 
the liquid in a vacuum until the desired concentration has 
been reached. The finished product is a thick, colorless, 
transparent liquid known as glucose, or corn sirup. For- 
merly sulphurous acid was added to prevent .its turning 
yellow. On account of the pure-food agitation this prac- 
tice has been disconthiued except when the glucose is ex- 
ported to countries where the presence of sulphurous acid 
is not prohibited. 

Composition of corn sirup. Glucose, or corn sirup, there- 
fore, is a solution of dextrose and dextrine and similar 
sugars, in smaller amount, as formed by the chemical com- 
bination of water and starch. These compounds are formed 
whenever starch is heated to the proper temperature. How- 
ever, Avhen moist starch is heated, dextrine is the main 
product produced. This is quickly hydrolyzed by the 
saliva, forming maltose and dextrose, which give the sweet 
taste. For this reason a baked potato is sweeter than a 
boiled potato, and the crust of bread sweeter than the in- 
terior. Many natural products, especially fruits, contain 
large quantities of the same compounds. Honey is a nat- 
ural " sirup," which is very similar in composition to glu- 
cose, or corn sirup, containing dextrose, levulose, and 
sucrose, but no maltose. The only compound present in 



CARBOHYDKATES 97 

glucose Avhicli is not derived from tlie starch is the salt 
formed by the neutralization of the hydrochloric acid with 
soda ash. The word '' glucose '' means sweet and was adopted 
for this reason. The name '' corn sirup " has been adopted in 
this country because it is made from corn and has the 
physical properties of a sirup. In Europe, however, glucose 
is made almost entirely from potato starch and sometimes 
from broken and low-grade rice. 

Table sirup. JNlost of the table and cooking sirups on 
the market to-day are composed very largely of corn sirup. 
It cannot be used in the pure state for this purpose because 
it is quite insipid. It is therefore blended with "refiners' 
sirup," or molasses from the sugar refiners, which has 
generally too strong a flavor to be used alone. Glucose is 
also very extensively used in the manufacture of candy. 
It is also largely used in the manufacture of jams, jellies, 
and otlier fruit preparations, as well as for many other 
minor purposes. 

Nutritive value of glucose. Because glucose is rarely 
ever sold at retail in the pure state under its own name, 
or used as such in the household, but has invariably been 
sold in combination with some other food and under some 
other name, Avithout any statement or intimation of its 
presence, it has almost universally been considered an 
adulterant. This classification has been correct because the 
purchaser almost always was under the impression that 
sugar had been used in the preparation of the product ob- 
tained. The assumption that glucose is unwholesome or 
injurious or even of little or no food value is absolutely 
erroneous. On the contrary, it is a highly nutritious food, 
having an energy value of 1777 calories per pound, and is 
very readily digested and assimilated. It is inferior to cane 
sugar only in the matter of flavor. The only valid objection 



98 PURE FOODS 

to its use is removed when, in accordance with pure-food 
laws, its presence is indicated on the label of foods which 
contain it. 

Amount of corn used in producing corn products. Glucose 
will probably continue in the future, as in the past, to be an 
important part of our food supply. This is evident from 
the fact that about 36,000,000 bushels of corn are used 
annually for its manufacture in the United States. This 
amount of corn would require about 36,000 cars to haul 
it, and would make a single pile almost as high (500 feet) 
as Washington Monument (555 feet) in our national capi- 
tal. This pile would be 500 feet high, with a base covering 
a space equal to several city blocks ; that is, 500 feet long 
and 500 feet wide. There are made annually 1,000,000,000 
pounds of corn sirup, which is sufficient to give to every 
man, woman, and child in the United States 12 pounds 
per annum. 

Manufacture of cane sugar. The process of manufactur- 
ing ordinary sugar is much simpler. It exists as such in 
the juices of the sugar cane and sugar beet. The sugar cane 
is cut down and passed through presses, which squeeze out 
the juice. After the addition of a little slaked lime to 
remove impurities and to keep the juice alkaline, it is evapo- 
rated and the sugar crystallizes out. This is the raw or 
brown sugar. The sirup remaining after the sugar has been 
crystallized out is known as molasses. It contains the min- 
eral matter present in the juices of the cane as well as any 
impurities which may have been introduced during the 
process. Raw sugar is also obtained from beets, the sugar 
in this case being dissolved out of the tissues of the finely 
divided beets by a process of diffusion. 

Refining of cane sugar. In order to refine the crude sugar 
it is first moistened with sirup to dissolve the impurities 



CARBOHYDRATES 99 

and placed in a centrifuge. When this machine is rotated 
at a high speed, the sirup is thrown off the sugar crystals. 
These are then dissolved in water and phosphoric acid and 
lime added. The calcium phosphate formed in this manner 
carries down the suspended impurities, which are filtered 
off by means of canvas bags. The sirup is then filtered 
through bone char and concentrated in vacuum pans in 
exactly the same manner as the corn sirup. From the con- 
centrated sirup the sugar crystallizes out and is placed in 
the centrifuge, where it is washed with water and then 
sprinkled with water containing a small amount of Prus- 
sian blue in order to counteract a slight yellowish tinge. 
After drying, the sugar is ready for sale. 

EXPERIMENTS 

22. Starch test. Test for starch several cereals and vegetables, 
as corn, wheat, potatoes, etc. The starch test may often be obtained 
on vegetables by applying a drop or two of iodine solution (pre- 
pared as in Experiment 1) to the freshly cut surface of the vege- 
tables. The test may be obtained in all cases by crushing a small 
portion of the vegetable or grain and treating with boiling hot 
water for a few minutes. On allowing to cool and adding a few 
drops of the iodine solution a deep blue coloration or precipitate 
is produced. 

23. Conversion of starch into sugar. The conversion of starch into 
sugar may be shown by the following experiment : Starch paste 
is first made by moistening a few grains of starch with water and 
adding boiling water with constant stirring. A few cubic centi- 
meters of hydrochloric acid are added and the boiling continued. 
Before adding the acid a few drops of the starch solution is diluted 
with water and iodine solution added. This test is repeated at five- 
minute intervals. At each successive test the blue color becomes 
fainter until replaced by a brown color, indicating that the conver- 
sion of the starch is completed. 

The solution may now be neutralized with sodium carbonate, 
which is added until the solution no longer turns blue litmus paper 



100 PURE FOODS 

red. It is generally quite cloudy at this point and should be filtered. 
It may then be concentrated by boiling until a sirupy consistency is 
reached. 

24. Action of diastase on starch. The natural process of conver- 
sion of starch into sugar by the enzymes present in the grains may 
be shown as follows : 26 gm. of malt are ground in a mortar 
and treated with 1 ccm. of cold distilled water for an hour and then 
filtered. The diastase of the malt is dissolved by the water. Equal 
parts of this solution and some thin starch paste are mixed and kept 
at a temperature of 55° C. The conversion of the, starch may be 
observed by means of the iodine test, as directed in Experiment 22. 

Various malt extracts (maltine for instance) may be purchased 
and used in place of the diastase extracted directly from the malt. 
The rapidity with which equal portions of such extracts convert the 
same starch solution may be used as a measure of their strength. 

25. Digestion of starch. The conversion of starch into sugar by the 
natural process of digestion may be illustrated ])y the following 
experiment : A few cubic centimeters of saliva are collected and 
filtered. A solution of boiled starch is j)repared and cooled as directed 
in Experiment 22. The saliva is added, using about 10 ccm. to 100 
ccm. of the starch solution. One half of the mixture is made slightly 
acid with hydrochloric acid. Both portions are tested with the iodine 
solution at regular intervals. It will be found that no conversion 
takes place in the acid solution. This shows how the acid gastric 
juice of the stomach stops the action of the saliva, and emphasizes 
the necessity of chewing the food and the evils of rapid eating. 
The starch in the alkaline solution will l)e more or less rapidly con- 
verted, depending upon the activity of the saliva, temj^erature, and 
amount of starch present. 



CHAPTER X 

CANDIES 

Cocoa and Chocolate 

Function of sugar in the diet. Sugars and sirups are used 
by many people for condimental purposes only; that is, 
they are added to foods for the purpose of giving a. pleasant 
taste. As has been shown in the preceding chapter, these 
substances have a high energy value ; indeed, most of the 
energy used by the human system is derived from this class 
of foods (the carbohydrates). So that when sugar is added 
to tea or coffee or any other food, its energy or food value 
is materially increased, the calorific value of sugar being 
1860 calories per pound. The same is true of sirups, 
honey, and other sweet foods. While they are very palat- 
able, they are also very nourishing, so that the energy 
available for the system is greatly increased by their 
consumption. 

Food value of candy. Candy is generally eaten between 
meals without any thought of its food value. The grati- 
fication of the taste is frequently the only object sought, 
with the result that the system is overloaded and more or 
less serious consequences follow. This is more likely to 
happen on account of the very high calorific value of many 
constituents of candy. While glucose with 1777 calories 
has the same calorific value as sugar, chocolate has a much 
higher value ; that is, 2861 calories per pound. Nuts have 
a similar value, peanuts, for example, giving 2560 calories. 

101 



102 



PUKE FOODS 



Compared with these values, we find that the average value 
for meats is about 1000 calories, while vegetables and fish 
seldom give more than 500 calories. 

Adult ration of candy and nuts. Candy must therefore 
be looked upon as one of our most highly concentrated and 
nourishing foods. This is strikingly illustrated by the fact 
that one and two-thirds pounds of chocolate creams give 
3000 calories of energy, the equivalent of a day's ration 
for an active adult. As chocolate creams are composed 
almost entirely of carbohydrates, they would constitute a 
very poorly balanced ration. If part of the candy were re- 
placed by peanuts, another highly concentrated food which 
is largely consumed between meals, a better balanced ration 
would be obtained. The following table gives the com- 
position of a daily ration containing two thirds of a pound 

TABLE XX 

Adult Ration composkd of Two Thirds of a Pound of Choc- 
OLATK Creams and Two Thirds of a Pound of Peanuts 





Peanuts 


Chocolate 
creams 


Total 


Calories 


1774 


1200 


2974 




Grams 


Grams 


Grains 


Protein 


75 


7 


82 


Fats 


110 


26 


136 


Carbohydrates .... 


73 


220 


21)3 



of peanuts and two thirds of a pound of chocolate creams. 
It is evident that not only are the required number of 
calories of energy obtained, but that the proper proportion 
between protein, fats, and carbohydrates is maintained in 
this small amount of two articles generally eaten at odd 
times merely to indulge the sense of taste. 



CANDIES 103 

Such a diet would uot be desirable, because all of the 
carbohydrates would be present iii very soluble form, a con- 
siderable portion of which should be replaced by starch. 

Candy not a sustaining food. The fact that a taste for 
candy does not have to be acquired, but that every one has 
a natural appetite for such food, undoubtedly has a physio- 
logical explanation. This natural taste would seem to in- 
dicate a demand of the system for these very nourishing 
foods. The appetite seems to say, " Here is a food ready 
for use which can give me a great deal of energy very 
quickly." It is not, however, a sustaining food. One does 
not feel satisfied for any considerable length of time, as 
after eating an ordinary dinner. It goes into the blood 
quickly and is soon used up. Starch is a much better food, 
because it is digested more slowly, giving the system 
nourishment as it is required. Peanuts also could not be 
eaten continually in large quantities, on account of the 
presence of some constituent in small quantity which the 
system does not tolerate. It is evident, however, that sweet- 
meats have a very high food value and should not be eaten 
in large quantities in addition to the ordinary meals, neither 
should they be eaten to the exclusion of the former. 

Sugars present in candy. The manufacture of sugar and 
glucose, which constitutes the larger part of most candy, 
has been described in the preceding- chapter. Sugar con- 
sists mainly of one substance, sucrose, represented by the 
chemical formula 012^22^11* Grhicose is a mixture of a 
number of chemical compounds, although dextrose, mal- 
tose, and dextrine are the important constituents. ^Maltose 
has about the same formula as sucrose, Cj2H220i-^ • H2O. 
Dextrose has the formula CgHj20g, while dextrine is repre- 
sented by the simpler formula CgHjoO^. When sugar is 
heated in the presence of an acid, the sucrose is broken 



104 PURE FOODS 

down into two constituents, dextrose and levulose. These 
compounds are very similar to glucose in their properties. 
In making candy, therefore, very nearly the same result 
maybe obtained by using a combination of sugar and glucose, 
or by simply boiling sugar with an appropriate acid, such 
as tartaric. The same decomposition takes place in the 
stomach when sugar is digested. There is very little candy 
made from pure sugar without glucose. These two con- 
stituents are equally wholesome and nutritious. While 
glucose is transparent and absolutely colorless when pro- 
duced, it very soon begins to turn light yellow. The candy 
made from glucose is also not pure white. This difficulty 
is entirely avoided by the addition of a small amount of 
sulphurous acid to the glucose or the candy. Until recently 
this was the common practice in the manufacture of candy 
and glucose. It has been largely discontinued on account 
of the widespread belief that sulphurous acid is unwhole- 
some, and the enactment of laws forbidding its use in 
articles of food. 

Sulphurous acid injurious. On account of the small 
amounts of sulphurous acid ordinarily used in foods, no 
immediate ill effects can usually be observed from consum- 
ing food containing it. It has been shown, however, that 
the continual consum23tion of such foods tends ultimately 
to produce disease, especially of the kidneys, through which 
the acid must be eliminated. There is also the danger that, 
if its use in foods is allowed, excessive amounts will occa- 
sionally be added by careless or unscrupulous manufac- 
turers, subjecting the consumer to very serious danger. 
Formerly sulphuric acid was very largely used in the man- 
ufacture of glucose. This acid was neutralized with lime, 
producing calcium sulphate, some of which remained in 
the glucose. While there is more objection to the presence 



ca:n^dies 



105 




Fig. 21. The Cocoa Tree, showing the Fruit growing on the Trunk 

of this compound than to the presence of the salt whicli 
remains in the glucose as made at present with hydro-, 
chloric acid, it cannot be said that calcium sulphate is 
injurious in moderate amounts. This is evident from the 



106 PUKE FOODS 

fact that almost all natural waters used for drinking con- 
tain this substance. 

Food value of chocolate creams. Chocolate is another 
very common constituent of candy. In the United States 
chocolate creams are the most popular and largely sold of 
all candies. The popular taste in this instance seems to 
have a correct physiological basis, smce chocolate creams 
contain all the elements of a complete diet, namely fats, 
protein, and carbohydrates. Tlie flavoring matter of the 
chocolate is also very agreeable to most palates. 

History of cocoa. Chocolate is made from the cocoa bean, 
which grows on a tree which is indigenous to Central 
America. It was discovered by Cortes during his conquest 
of Mexico. The Mexicans had cultivated the tree and used 
the bean in much the same manner as we do at present. 
Cortes introduced its use mto Spain, where it soon became 
very popular. From Spam its use spread to Italy, thence 
to France and to England. The young American colonists 
learned its use from the mother country, and as the people 
of the United States have prospered, the consumption of 
the products of the cocoa bean have steadily and rapidly 
increased, in spite of the fact that its use is generally con- 
sidered a luxury. The botanist Linnseus gave it its name 
Theohroma cacao. Theohroma means "food of the gods," and 
undoubtedly was designed to express Linnaeus' opinion of 
the delicate flavor of the bean. The word ''cacao" is the 
Mexican name of the plant. 

The cocoa tree. This tree flourishes both wild and culti- 
vated in warm moist climates, such as Mexico and Central 
America, parts of South America, and other tropical regions. 
It grows best in sheltered valleys where a soft rich soil is 
kept moist by a neighboring river, and where it is sheltered 
by other and taller trees. Under these conditions it blossoms 



CANDIES 107 

throughout the entire year. It has red flowers, which develop 
into a yellow fruit, about one thousand flowers being required 
to produce a single fruit. This is large, about 10 inches 
long by 4 inches wide. The soft pulp surrounds from 25 
to 40 seeds, which are the cocoa beans of commerce. The 
fruit ripens at all times of the year, as is customary with 
tropical vegetation. The fruit is cut off the tree, split 
0|)en, and the beans removed, and in some localities dried 




Fig. 22. Gathering the Cocoa Fruit 

immediately in the sun. The better grades are first sub- 
jected to a fermentation process, which destroys certain 
bitter constituents. 

Roasting the beans. The flavor and other properties of 
the beans differ with the country in which they are grown. 
By carefully selecting and mixmg different varieties of 
beans the best flavored chocolate is produced. When the 
beans are first brought to the factory, sticks, stones, and 
dust must be removed and the beans sorted to even sizes. 
The next process is the roastmg of the bean. This is done 



108 PUKE FOODS 

by placing the raw beans in a steel cylinder, which is heated 
and revolved until the beans are uniformly roasted. The 
roasting develops the odor and flavor of the beans, gives 
them a brown color, and removes the stringent taste of the 
raw bean. 

Cocoa hulls. Tlie roasted beans are next placed in a 
machine in which the hulls are broken off and blown away. 
In the next operation the beans are crushed and the radical 
removed. The radical is a small germ from which the plant 
grows when the bean is allowed to sprout. About 16 per 
cent of the weight of the bean is lost in roasting and hull- 
ing, some of which is due to loss of moisture. A little of 
tlie fat also goes into the hulls, which contain 5 per cent of 
fat and about 0.8 per cent of theobromine. When boiled in 
water a liquid is obtained which has some of the properties 
of cocoa, but is of very little value as such. The hulls 
have been largely used as an adulterant. For this purpose 
they are ground and mixed with cocoa, spices, etc. They 
have some value as cattle food. 

Cocoa butter. The meats of tlie beans, known as cocoa 
nibs, are next ground in stone mills. There are usually three 
mills in a set, so that the beans are ground three times. 
This reduces them to a thin paste, which is known as 
unsweetened chocolate, and which on coolhig becomes a 
hard cake. It contains about 50 per cent of fat. From 40 
to 50 per cent of this fat may be removed by subjecting 
tlie chocolate to moderate pressure m a hydraulic press, 
while if subjected to a pressure of 4500 pounds per square 
hich, 60 per cent of the fat may be removed. This fat is solid 
at the ordinary temperatures and is known as cocoa butter. 
It is used to a considerable extent in pharmaceutical and 
medical preparations, but most largely in the preparation 
of chocolate bars and the chocolate coating of candy. 




109 



110 PURE FOODS 

Breakfast cocoas. These are prepared by grinding to a 
powder the chocolate from which a portion of the cocoa 
bntter has been pressed out. The amount of fat remaining 
in the cocoa varies with the different brands. All of the 
fat contained in the chocolate cannot be allowed to remam, 
because the resulting cocoa would be too rich and indi- 
gestible for most people. As from 40 to 60 per cent of the 
cocoa butter is removed by means of hydraulic pressure, 
cocoa will contain from 28 to 38 per cent of fat, while 
unsweetened chocolate contains 50 per cent. In the prep- 
aration of some of the brands the cocoa is treated in such 
a manner that the fat which remains is more readily emulsi- 
fied by water. By the Dutch process the cocoa is treated 
with hot water and alkalies, such as potassium, sodium, or 
magnesium carbonate. In the German process ammonia 
or ammonium carbonate is used. This results in the pro- 
duction of a purer cocoa, as in the subsequent roasting the 
ammonium compounds are entirely expelled, while the 
soda, potash, or magnesia introduced by the Dutch process 
remain in the finished cocoa. The presence of these con- 
stituents may be desirable for some people, while they 
could never be considered injurious. After a treatment of 
this kind the cocoa is powdered and is ready for use. The 
treatment with the alkalies has changed the cocoa in such 
a way that it remains suspended when boiled with water or 
milk, and does not so readily settle to the bottom of the 
vessel. The fat of the cocoa is also very probably rendered 
more easily digestible. Breakfast cocoa also contains from 
6 to 24 per cent of proteids as well as from 14 to 28 per cent 
of starch and fiber (Table XXI, p. 112). Cocoa, therefore, 
contains all the constituents of a complete diet in quite large 
proportions. As the amount of water is small and proteids 
are generally expensive, cocoa is also a relatively cheap food. 




Ill 



11: 



PUKE FOODS 



Composition of breakfast cocoas. The following table gives 
the conipositioii of a number of the well-known brands of 
breakfast cocoa on the market to-day : 



TABLE XXI 
Composition of BrjEAKFASx Cocoas 



Brand 


Water 


Ash 


Fat 


Theo- 
bromine 


Starch, 
fiher, etc. 


Protein 




Per cent 


Per ceni 


Per cent 


Per cent 


Per cent 


Per cent 


Huyler .... 


4.27 


5.54 


34.04 


1.02 


18.70 


17.29 


Miller 


3.99 


4.05 


38.70 


1.06 


24.17 


6.77 


Fry 


4.33 


4.28 


31.16 


1.36 


28.23 


12.78 


Walter Baker . . 


6.02 


4.70 


29.30 


1.28 


14.66 


19.53 


Van Houteii (Dutch) 


4.53 


8.19. 


29.78 


0.09 


29.96 


17.03 


Bensdorp (Dutch) 


4.59 


6.09 


33.06 


0,88 


19.85 


11.41 


Wilbur .... 


3.84 


4.69 


33.32 


0.82 


22.78 


16.74 


Cadbury .... 


4.00 


4.70 


27.58 


0.70 


27.53 


13.58 


Whitman . . . 


2.70 


4.15 


37.68 


0.66 


20.36 


14.13 


Lowney .... 


3.20 


5.43 


23.00 




17.68 


24.88 



The large amount of ash in the Van Houten and Bens- 
dorp brands, which are Dutch cocoas, is due to the presence 
of the alkalies introduced in the process of manufacture. 
It is evident that cocoa contains a great deal of nourish- 
ment, and that the beverage, especially when prepared with 
milk, has a high nutritive value in addition to the stimu- 
lating properties given to it by the theobromine and caffeine. 
Coffee and tea have similar stimulating properties but very 
little food value. 

Adulteration of cocoa. While the removal of a portion 
of the fat of the chocolate for the manufacture of cocoa is 
desirable, the tendency is to reduce the amount of this con- 
stituent to the least that is acceptable to the public, on 
account of the high price and great demand for the cocoa 




113 



114 



PUEE FOOD>S 



butter. Cocoa is also easily adulterated by the addition 
of the ground hulls, which have very little food value and 
little or no commercial value. 

Chocolate. This is the name by which the ground cocoa 
bean from which no fat has been removed, is known. It is 
used pure and mixed with cocoa butter and sugar. The 
quantity of sugar varies from 50 to 70 per cent, while about 
21 per cent of fat must be present. Its composition and 
that of chocolate creams is given in the following table : 



TABLE XXII 
Co^MPosiTiON OF Chocolate and Pkanuts 





Peanuts 


Chocolate 


Choco- 




Pure 


Sweet 


CREAMS 


Calories 


2560 


2860 


2131 


1800 






Carbohydrates .".... 

Sugar 

Starch ....:. 
Fat 


Per cent 
25 

38 
26 

2 

9 


Per cent 
27.6 

50 
12 

1 

0.4 

3 

3 

3 


Per cen t 

57 
9.2 

16.7 
4.0 
0.4 
0.1 
1.0 
1.0 

10.6 


Per cent 

79.4 
2.76 
5.00 


Proteids 

Theobromine 

Caffeine 

Fiber 

Ash 


1.2 

0.1 

0.04 

0.3 

0.3 


Water 


10.6 



It is evident from the table that the addition of sugar ren- 
ders chocolate a better food because the unmixed product 
contains a larger percentage of fat than most people can 
readily assimilate. The addition of the sugar very mate- 
rially reduces the percentage of protein. This element can 
readily be supplied by other foods. 




pq 



li: 



116 PUEE FOODS 

Chocolate creams. In the manufacture of chocolate 
creams, cocoa butter is added to the chocolate in order to 
give the glossy appearance to the coating. The interior of 
the cream is composed of sugar and glucose, although 
various fruit jellies, nuts, etc., are dipped in chocolate in 
order to give variety to the candy. Fig. 28 shows a part 
of this process. On the right are seen double boilers in 
which the fondant is mixed with flavoring matter; on 
the left are seen the automatic molding machines wherein 
the fondant is cast in molds before being coated with choc- 
olate. A large number of chocolate preparations have been 
made and sold, such ingredients as milk, cream, malt, 
oatmeal, nuts, etc., being used. Plain chocolate in bars, 
containmg GO per cent of sugar and 40 per cent of choco- 
late, is very popular in Europe. A thin coat of shellac 
varnish is very commonly used on cliocolate and other 
candies in order to form a liard protective coating and 
prevent the candy from absorbhig moisture and sticking 
together. 

Adulteration of chocolate. Chocolate has been subjected 
to considerable adulteration. In the first place, the rather 
expensive cocoa butter has been replaced with various 
cheaper fats, such as beef stearin and coconut-oil stearin. 
A bean known as St.-John's-bread is sometimes ground 
and mixed with chocolate. This bean is quite sweet and 
has a fairly agreeable odor. A still more reprehensible 
practice consists in making an imitation chocolate from a 
mixture of iron oxide, gelatin, and sugar. The iron oxide 
is dark red and resembles the chocolate very closely. The 
gelatin gives the proper consistency to the mixture, and 
the gloss produced by the fat of true chocolate is imitated 
by a coating of sliellac varnish. If the color of the choco- 
late cannot be matched, a little aniline dye is added. 




117 



118 PUEE FOODS 

Use of eggs in candy. A considerable number of other 
substances are used in small amount in candies. Among 
these are eggs. Since on account of natural causes, a large 
proportion of the eggs produced are obtained during the 
spring and summer months, while the consumption of this 
excellent food is distributed quite uniformly throughout 
the year, considerable difficulty is experienced in obtain- 
ing a supply of fresh eggs at all times. The candy manu- 
facturer can quite easily utilize eggs preserved m such 
manner that they could not be sold to the ordinary con- 
sumer. Dried eggs are very convenient for the manufac- 
turer. In countries where the supply exceeds the demand, 
the contents of the egg are removed from the shell and 
the yolk and white separated and dried. The yolk pro- 
duces a powder , while the white produces flakes. As no 
portion of the food value of the egg is lost in this process, 
there can be no objection to the use of dried eggs, provided 
the process is carried out in a sanitary manner. At times, 
however, boric acid or other preservative is introduced, 
which remains in the candy. A still more reprehensible 
practice consists in the transportation of the broken eggs 
in the liquid state preserved with boric acid or formalde- 
hyde. This practice has been largely prevented by the 
efforts of the pure-food authorities. 

Gelatin. Eggs may be entirely replaced in candies by 
gelatin, which is considerably cheaper. Aside from its low 
nourishing properties, there can be no objection to this 
practice if a good grade of pure gelatin is used. 

Coloring matter. This is very largely used in candies. 
While it is considered fraudulent to color or dye many 
food products, this is not true in general of candies. If 
some substance is colored to imitate chocolate, and thereby 
deceive the consumer, it would be considered illegal. 




119 




120 



CANDIES 121 

There is no attempt at deceit, however, in coloring most 
candies. Consumers are generally aware that the coloring 
matter is added merely to please the eye. It is very essen- 
tial, however, that the dye used shall be absolutely harm- 
less. This question will be discussed in the next chapter. 

Flavoring matter of all kinds is also used in large quan- 
tities in candies. The same requirement holds good here 
that the flavoring matter must be Avholesome. This subject 
is fully discussed in Chapter XVIII. 

EXPERIMENT 

26. Detection of glucose. As glucu.se contains a considerable amount 
of dextrin, which is insoluble in methyl alcohol, the presence of 
glucose in candy and other foods may be tested for in a very simple 
manner. A concentrated solution of the candy is nuide by dissolv- 
ing the sam[)le in two or three times its volume of water. The solu- 
tion is allowed to settle, or is filtered if insoluble matter is present. 
On adding methyl alcohol (wood alcohol) with constant stirring, a 
heavy white precipitate indicates the presence of glucose. Gelatin 
and soluble starch would also be precipitated by the alcohol. 

Sirups, honey, etc., may be examined for the presence of corn 
sirup in the same manner. The sami)le is diluted with an equal 
volume of water and the methyl alcohol added. 



CHAPTER XI 

ANILINE DYES AND OTHER FOOD COLORS 

Fraudulent coloring of foods. The artificial coloring of 
foods has been very generally regarded as a fraudulent prac- 
tice. The color and general appearance of many foods is 
so commonly used as a criterion of quality and condition 
that any attempt to alter tlie natural appearance by the 
introduction of foreign coloring matter at once arouses tlie 
suspicion that an attempt is being made to cover defects 
and to deceive the consumer into thinking that the food in 
question is better than it actually is. Coloring matter is 
frequently introduced in order to create the impression 
that a given constituent is present when it is entirely 
absent. A common instance of this practice is the use of 
yellow coloring matter in cakes as a substitute for eggs. 
Such coloring matter has been sold to bakers under such 
names as '' egg substitute," etc. When, in addition to these 
obviously fraudulent practices, the fact is taken into con- 
sideration that aniline dyes have been very extensively 
used in foods, and that many of these compounds are ex- 
tremely poisonous, the opposition to the use of any color- 
ing matter Avhatever in foods seems fully justified. 

Harmless coloring. It has been shown, however, in the 
chapter on candies, that the introduction of coloring matter 
into sweetmeats does not deceive the public. In other cases 
the statement on the label of a food that it has been artifi- 
cially colored would remove in a large measure the objec- 
tions to the practice. Of course no coloring matter which 

122 



ANILINE DYES AND OTHER FOOD COLORS 123 

is at all poisonous should, under any circumstances, be 
introduced into foods. 

Vegetable colors. Two classes of coloring matter have 
been used in foods, namely vegetable colors and aniline 
dyes. The former are obtained by extracting the natural 
coloring matter from some portion of a given plant. The 
wood of a number of tropical trees has been largely used 
for this purpose, such as barbary, Brazil, fustic, Lima, and 
saffron. In this class is generally included the dye cochineal, 
which is obtained from a bug wliich is collected and dried 
in Mexico and other tropical countries. Butter was for- 
merly often colored on the farm by means of the yellow 
color extracted from carrots. 

The aniline dyes, on the other hand, are produced from 
compounds which are distilled out of coal tar and combnied 
Avith various chemical reagents. 

Poisonous vegetable colors. While it would seem that 
the vegetable colors would be more wholesome than the 
coal-tar dyes, this cannot be assumed, because some of the 
most violent poisons known are obtained from vegetables. 
Only when the color is obtained from a vegetable which is 
known to be wholesome can this be assumed. The vegetable 
colors lack tlie brilliancy and high tinting power of the 
mineral colors, and are also far less permanent, so that in 
many cases they are destroyed when put into food which 
is boiled for any length of time. Attempts have been made 
to render these more permanent by the introduction of 
muieral constituents such as sulphuric acid. In such proc- 
esses mineral poisons are liable to be introduced, so that 
vegetable colors treated in this manner must be considered 
as partly mineral in character. 

Poisonous aniline dyes. Aniline dyes may be poisonous 
for several reasons, which must be clearly differentiated. 



124 PURE FOODS 

In the first place, the chemical compound which gives the 
color may be poisonous. On the other hand, if this is harm- 
less, the dye as manufactured and sold may be poisonous, 
because other poisonous substances introduced in the proc- 
ess of manufacture may not have been entirely eliminated. 
Among such substances, arsenic is the most common. This 
element is very widely distributed in the earth, so that it is 
present in small amount in a great many chemical com- 
pounds unless the greatest care has been taken to eliminate 
it. If such a compound has been used in the manufacture 
of a given dye, some or all of the arsenic may remain in the 
dye. For a great many purposes for which aniline dyes are 
used, the presence of a small amount of arsenic is not 
objectionable. Dyes which are designed for food purposes 
must be entirely free from this element. The manufacture 
of aniline dyes which are entirely free from arsenic requires 
the very greatest technical skill and care, which tends to 
greatly increase the cost of such dyes. The color of many 
dyes is rendered more brilliant or clianged in shade if the 
dye is allowed to combine Avith a metallic compound. As 
many of the metals form poisonous compounds, dyes treated 
in this manner cannot be used for food purposes. 

Methods of proving dyes harmless. A great many experi- 
ments have been conducted on pure aniline dyes which 
contained no poisonous impurities, to ascertain if the dye 
itself is poisonous or harmless. Such experiments have 
been carried out in various ways. Small animals such as 
rabbits and dogs have been fed with food containing the 
dye being tested. The effect on the animals was carefully 
noted, the dye being fed in varying amounts and for long 
periods of time, if it proved to be comparatively harmless. 
In the latter case experiments have been carried out on 
human beings. In the case of poisonous dyes a record has 



AjN^iline dyes and other food colors 125 

been made of cases in which such dyes have been taken by 
human beings by mistake or with suicidal intent. Investi- 
gations have also been conducted as to the health of work- 
men employed in factories Avhere dyes are manufactured. 
Such workmen are lial)le to inhale dust containing the dye, 
or to take food or drink containing small quantities of it. 

Experiments with a poisonous dye. The following experi- 
ments indicate the character of the evidence obtained in 
this manner. Experiments with dinitrocresol or saffron 
substitute resulted as follows: 0.25 gm. was administered 
to rabbits. The respiration became rapid and the animals 
soon fell to the ground. Spasms followed, and finally death 
in from twenty to thirty minutes. Dogs died with similar 
symptoms from doses as small as 0.1 gm. A woman died 
in five hours after takino- 4.5 grm. of saffron substitute. 
This dye is clearly a very dangerous poison. 

Experiments with a harmless dye. The following experi- 
ments were carried out with fuchsin. Two rabbits Avere 
fed J^ gm. of the dye in 50 gm. of barley daily for sev- 
eral weeks without showing au}^ bad effects whatever. Otlier 
rabbits were fed 15 gm. of the dye in 15 gm. of barley 
for two weeks without showing any ill effects. One per 
cent solutions of the dye were injected directly into the 
blood of rabbits without showing any ill effects. Dogs were 
fed 20 gm. daily, while a man took 3^ gm. in a week 
without showing any ill effects. An investigation of the 
health of 52 workmen employed in a fuchsin factory gave 
the following results: No ill health could be observed 
among the workmen, although six had been employed for 
three to four years, six for four to six years, eleven for 
six to ten years, and five for eleven to eighteen years. It 
was concluded from the experiments that fuchsin could be 
safely employed as a food color. 



126 PURE FOODS 

Dyes permitted by the United States Department of Agri- 
culture. This department has prepared a list ^ of the anihiie 
dyes which have been sliown to be absolutely harmless. 
The use of other aniline dyes in foods is illegal, and the 
dyes Avhicli are allowed must be free from any other color- 
ing matter as well as from any contamination due to imper- 
fect or incomplete manufacture. The use of these dyes is 
also illegal Avhen the object sought is to conceal damage 
or inferiority. 

Amount of dyes used in food. The amount of dye com- 
monly used in foods is very small, so that only minute 
amounts are ordinarily consumed by a single individual. 
One ounce is generally sufficient to color from twenty-five 
to thirty-five pounds of candy. This accounts for the fact 
that a relatively small number of cases of serious poisoning 
have occurred during the many years Avhen manufacturers 
were under very little restraint as to the dyes which were 
used. 

Harmless vegetable dyes. A number of vegetable colors 
are in common \ise and are entirely harmless. Among these 
are turmeric, cochineal, annatto, indigo, litmus, and saffron. 

The tests for aniline and A'egetable dyes are given in 
Chapter XIII. 

1 Food Inspection Decision 70. The list contains seven dyes as follows: 
The numbers are given as listed in A. G. Green's edition of the Schultz-.Julius 
Systematic Survey of the Organic Coloring Matters (1904). The list is as 
follows : 

Red shades Yellow shade 

107. Amaranth 4. Naphthol yellow S. 

56. Ponceau 3 R. Green shade 

517. Erythrosin 435. Light green S. F. yellowish 

Orange shade Blue shade 

85. Orange I. 692. Indigo disulfoacid 

This list was prepared for the Department of Agriculture by Dr. Bernhard 
C. Hesse of New York City, who is an expert on dyes. 



CHAPTER XII 

PRESERVATION OF FOODS 

Modern people well fed. Tlie certainty and regularity 
witli which modern civiHzed man is supplied with his daily 
food would liave astonished and delighted the people living- 
only a few hundred years ago. Famine can no longer exist 
except among savages and in semicivilized countries. Civi- 
lized man not only expects a bounteous supply of all 
staple foods, but demands a regular supply of dainties and 
luxuries at all seasons of the year. No generation has been 
fed so well as the people of to-day. This certainty of the 
food supply has rendered it possible for men to give their 
undivided attention to the development of the arts and 
sciences, and accounts in no small measure for the remark- 
able progress made in our industrial life, and for the scientific 
achievements of the age. 

Advantage of methods of preservation. The equal dis- 
tribution of all kinds of foods during all seasons througli- 
out all parts of civilized countries has been rendered 
possible by the development of the methods of preserva- 
tion and transportation of foods. Fresli milk is regularly 
shipped five hundred miles. Poultry, fish, and meats are 
kept in cold storage for many months. All kinds of foods 
have been successfully canned so as to be preserved for 
years. By the application of hothouse methods of horti- 
culture and rapid transportation from tropical countries, 
fresh vegetables and fruits may be obtained almost equally 
well at all seasons of the year. Although, on the whole, 

127 



128 PUEE FOODS 

man lias benefited greatly by modern methods of preserva- 
tion, it cannot be denied that some harm has resulted from 
the use of preserved foods, and that some methods which 
have been used should be condenmed. 

Methods of preservation in use. The decomposition of 
foods is almost entirely due to tlie action of bacteria, as has 
already been explained in the chapters on milk and bac- 
teria, so that any method of preservation of foods neces- 
sarily involves the destruction of the bacteria or arresting 
their development and growth, or, what is still better, pre- 
venting their entrance into food. The methods of preserva- 
tion of foods which have been used may be grouped into 
four classes as follows : 

1. Desiccation, or drying so as to reduce the percentage 
of water to a very small amount. 

2. Use of low temperature ; that is, from 10° C. or 00° F. 
to considerably below the freezing point. 

3. Use of high temperatures ; that is, from about 65° C. 
or 150° F. to considerably above the boiling point of water 
(about 120° C. or 248° F.). 

4. The addition of foreign substances known as preserv- 
atives. These may be divided into two groups as follows : 

a. Long-used preservatives, — salt, spices, sugar, vinegar, 
alcdhol, smoke, pyroligneous acid. 

/>. Modern chemical preservatives, — borax or boric acid, 
sodium benzoate or benzoic acid, sodium salicylate or sali- 
cylic acid, formaldehyde, fluorides, sulphurous acid or 
sulphites, and hydrogen peroxide. 

The proper use of each method. All of tliese methods 
owe their efficiency as preservatives to their influence on 
the life and growth of bacteria. We find that these minute 
organisms cannot grow in the absence of water, at rel- 
atively low or high temperatures, nor in the presence of 



PRESERVATION OF FOODS 129 

fixed amounts of a considerable nnmber of various sub- 
stances. It is important to know, Avith reference to a given 
method of preservation, not only liow the bacteria are 
affected, but also Avhat changes are produced in the flavor, 
nutritive value, and digestibility of the food preserved, and 
also whether the preservative itself is wholesome or not. 
Careful study will show that all methods of preservation 
are not equally well adapted to the preservation of a given 
food. The method chosen must not injure the flavor, 
digestibility, or appearance of the food. 1> oiling, for in- 
stance, is an excellent method of sterilizing foods for pres- 
ervation, but it very materially injures the flavor and 
reduces the digestibility of milk, while, on the other hand, 
fruits and especially vegetables are in many cases rendered 
much more palatable and digestible by being cooked. 

Preservation by drying. The preservation of foods by 
drying has been practiced from the earliest times, meats, 
fish, and fruits being treated in this manner. In hot, dry 
climates this process has been extensively practiced because 
no special precautions are needed to insure success. In a 
cooler cUmate, especially during damp weather, the food is 
apt to ferment and decompose before it is sufliciently desic- 
cated. To overcome this difticulty chemical preservatives 
are often added. In the case of fruits, suli)hurous acid is 
especially suited to this purpose because it preserves the 
color of the fruit, which would otherwise darken more or 
less during the process of drying. Recently fruits and 
vegetables have been dried by subjecting them to the 
action of artificially dried and heated air. This imitates 
the conditions found in countries having a hot, dry climate 
where no preservative is needed. In many ways this is an 
ideal method of preservation, as the flavor and solubility 
of many foods are but slightly affected, while sucli food is 



130 PURE FOODS 

easily handled and transported and can be kept in good 
condition for a very long period of time. Recently such a 
perishable food as milk has been successfully dried and 
reduced to a powder, which can be i^edissolved in water, 
reproducing the liquid milk. 

Sanitary conditions during drying. Recent investigations 
have shown that sufficient care is not always taken in the 
drying of fruits to maintain sanitary conditions, and that 
the exposure of fruits while drying to flies and other insects 
may lead to the deposition of eggs, which develop into the 
larvce of these insects and render the dried fruit unfit for 
human consumption. Through the rigid inspection by the 
United States Department of Agriculture fruits prepared 
under such conditions are l)eing condemned. A careful 
examination of dried fruits before consumption is always 
advisable. 

Refrigeration. Preservation by refrigeration also has the 
advantage that no foreign substance is introduced into the 
food, and only slight, if any, changes brought about in its 
composition or flavor. It has the advantage over desiccation 
in that tlie natural juices remain intact. This method is ad- 
mirably adapted to the preservation of meat, flsli, vegetables, 
fruits, poultry, eggs, milk, etc. Tlie same temperature is 
not suitable for all of these foods, and differs with the 
length of time it is desired to keep a given food. Fruits 
and vegetables must not be subjected to a freezing temper- 
ature, while meats, fish, and poultry can be preserved longer 
if frozen solid ; they must be thawed slowly, otherwise 
the meat becomes flabby. It is customary, when putting 
fish in cold storage, to freeze them solid and then dip the 
fish into cold water, so that a case of ice forms around 
the fish and remains while it is in cold storage, effectu- 
ally excluding all contamination. Investigators differ with 



PRESEKVATION OF FOODS 131 

reference to the length of time meats and other foods may 
be kept in cold storage withont deterioration. Some have 
conclnded that after three months meats begin to lose in 
flavor and nutritive value, while other investigators have 
concluded tliat if a sufficiently low temperature is employed, 
meats may be kept in good condition for years. As a matter 
of practice, eggs, poultry, fish, and game are kept from one 
season to 'the next; that is, on the average eight or nine 
months. For financial reasons no large amount of these 
foods can be held any longer. While the flavor of cold- 
storage food is somewhat impaired, its nutritive value is 
unafl^ected if it has been properly stored. 

Sterilization. High temperatures kill bacteria, while low 
temperatures merely retard or prevent their growth, unless 
continued for a long time. As has been explained in the 
chapter on bacteria, these organisms differ in their power 
to resist high temperatures. A very large proportion are 
destroyed at a comparatively low temperature. This fact 
is taken advantage of in the Pasteurization of milk. Such 
milk will remain sweet for several days. By sul)jecting the 
milk or other food product to a temperature somewhat 
above tlie boiling point of water, all bacteria and their 
spores are killed. This fact is utilized in the canning of 
fruits, meats, etc. If the containers of such food are prop- 
erly sealed, so that no bacteria can gain entrance, the food 
will remain unchanged for an indefinite time. This method 
of preservation is ideal for food Avhicli requires cooking 
before being eaten, and is therefore employed very largely 
with fruits, vegetables, fish, meats, etc. There is some 
danger that poisons may be introduced into the food from 
the container. The acids of fruits, for instance, will quite 
easily dissolve any lead which may be present in the solder, 
while the tin of the cans largely used as containers is 



132 PUKE FOODS 

acted upon more slowly. The tin must be pure and the 
soldering done in such a manner that none of this material 
comes in contact with the contents of the can. Glass and 
porcelain are the best materials for the- containers. 

Preservation by smoking. The fourth method of preserva- 
tion of foods by means of preservatives has been used from 
very early times. The use of smoke for the preservation of 
meat and fish was prol)ably discovered while men lived as 
savages. It is a very effective method, because smoke con- 
tains a very powerful antiseptic known as creosote. This 
and a number of other substances contained in smoke are 
highly poisonous, l)ut the amount of these substances which 
is present in preserved foods is so small that no ill results 
follow the use of such foods unless they are consumed con- 
tinuously to the exclusion of other foods. A quick process 
for produchig effects similar to smoking consists in dipping 
tlie meat in pyroligneous acid. This liquid is obtained by 
the dry distillation of wood and may be considered con- 
densed smoke. Meats cured in this manner are not of as 
fine a flavor as when smoked. 

Common salt. This has only slight preservative powers. 
It liinders the growth of bacteria only when present in fairly 
large amount, so as to form a fairly strong solution Avith 
any liquid present. It must also be considered a food, as it 
is an essential constituent of the serum of the blood. It is 
largely used as a seasoning or condiment, especially with 
vegetables. It is generally eaten in very much larger quan- 
tities than necessary to supply the needs of the system. The 
excess is eliminated largely througli the kidneys, requiring 
considerable labor by these frequently overworked organs. 

Vinegar and alcohol. These also have only slight preserva- 
tive powers, being efficient only when the acetic acid of the 
vinegar or the alcohol forms a fairly concentrated solution. 



PEESEKVATION OF FOODS 133 

Both of these substances are foods because tliey are oxidized 
in the system with the hberation of energy. As neither of 
them can be consumed in more than very moderate quanti- 
ties, without serious injury, they cannot be used to any 
great extent for the preservation of foods. 

Spices are added to foods mainly to improve the flavor. 
They assist very materially in digestion by stimulating the 
flow of the digestive fluids. Most of the spices have also 
marked preservative powers. Very few foods, however, can 
be spiced sufticiently to preserve them. 

Sugar in concentrated solution almost entirely prevents 
the growth of bacteria, while in dilute solutions they flourish 
and grow rapidly. For this reason jams and jellies do not 
readily spoil, while candies will keep almost indefinitely. 
As has already been shown, sugar is a highly concentrated 
food, so that the calorific value of food preserved in tliis 
manner is greatly increased and the essential characteristics 
of the fruits very nmch changed. 

Efficiency of chemical preservatives. The modern chemical 
preservatives are substances which have very high preserva- 
tive powers and no food or condimental properties what- 
ever. They have but one function in foods, except in one 
or two cases where they also serve to increase the natural 
color somewhat. Their very marked preservative power is 
evident from the fact that tliey are generally added to foods 
hi proportions of from 1-50,000 to 1-1000. In even the 
smaller of these proportions the effect is very marked. 

Chemical preservatives tasteless. The most important 
question in regard to these preservatives is whether they are 
themselves injurious to health, and whetlier foods to which 
they have been added are wholesome. This question is not 
raised in regard to the long-used preservatives, salt, vinegar, 
smoke, etc., although some of these contain substances Avhich 



134 PURE FOODS 

in concentrated form are violent poisons. The taste of these 
substances is so pronounced that their presence in foods is 
instantly detected, and their properties are so well known 
that there is no necessity of protecting the public by legal 
enactments. The chemical preservatives, on the other hand, 
give no evidence whatever by the sense of taste of their pres- 
ence. Having been used in foods for a comparatively short 
time, their effect on the human system is not thoroughly 
understood, while the claim has often been made that they 
are poisonous and that their use should be prohibited. 

The dose of poisons. In attempting to decide this question 
by experiments on animals and human beings, the fact is 
frequently overlooked that the quantity of a substance con- 
sumed has an important bearing on its effect on tlie animal 
organism. Minute doses of the most violent poisons may 
be taken with little or no effect. As the size of the dose is 
increased, the effects become more marked until the fatal 
dose is reached. Large doses are apt to be rejected and 
therefore not prove fatal. The size of the injurious or fatal 
dose differs not only with the poison but also with the indi- 
vidual. This personal peculiarity is called idiosyncrasy. 
In the case of animals this is strikingly illustrated by the 
fact that chickens can stand ten times and guinea pigs 
three times as much strychnine as is fatal to rabbits, while 
doofs can be given enoucrh corrosive sul)lhnate to sterilize 

o o o 

the entire digestive tract without fatal results. 

Cumulative poisons. While a snigle minute dose of most 
poisons can be taken without any noticeable effect, the 
repeated consumption of small doses of the same poisons 
leads to serious or even fatal results for two reasons : If the 
poison is cumulative, it will remahi in the system, so that 
numerous small doses may ultimately produce very much 
the same effect as a single large dose of the poison. Minute 



PRESERVATION OF FOODS 135 

doses of other poisons produce a slight injury to one or 
more organs of the body. Repeated doses increase the in- 
jury, until finally the organ affected breaks down utterly, 
and serious illness or death results in spite of the mar- 
velous recuperative power of the human system. 

Poisons commonly consumed. Human beings have from 
time immemorial consumed substances which must be classed 
as poisons. Among these are such well-known substances 
as alcohol and nicotine (the poisonous principle of tobacco). 
While the consumption of these substances in large quanti- 
ties is undoubtedly injurious and may even be fatal, it has 
been by no means demonstrated that they are injurious when 
consumed in small quantities. It is well known that adults 
are far less injuriously aft'ected by these poisons than is the 
case with the immature. Acetic acid, the active principle 
of vinegar, is a poison in concentrated form. jNIuriatic or 
hydrochloric acid is a poison, and yet it is always present 
in the stomach and aids digestion. Enough of this acid is 
produced and poured into the stomach during twenty-four 
hours to constitute a fatal dose if the total quantity were 
present at a given moment. 

Chemical preservatives are drugs. In studying the sub- 
stances which are used as preservatives in foods, it is found 
that all of tliem may be classed as drugs ; that is, they liave 
a specific effect on some function or organ of the liuman 
system, so that they are used as medicines. The medicinal 
dose of these substances varies from 5 to 40 grains, or from l 
to 2i- gm. With some foods enough would not ordinarily be 
consumed to give this amount, but in other cases a sufficient 
amount would be taken to produce physiological effects. 
While a healthy person might not suffer from such promis- 
cuous use of medicines, serious results might be produced 
with the sick or -weak. 



136 PURE FOODS 

Digestion experiments have been carried out iii the labora- 
tory with food treated with preservatives and subjected to 
tlie action of tlie digestive ferments, such as pepsin, rennin, 
amylopsin (pancreatic ferment), and trypsin. Tlie time 
required for the digestion is generally very much increased, 
although in some cases the digestion seems to be accelerated. 
Experiments have been carried out on animals. Dogs, pigs, 
and rabbits showed no ill effects when fed on food contain- 
ing borax or boric acid. Youncr kittens died when fed on 
milk containing borax, while kittens older than three months 
were not affected. In some histances where the animal 
seemed to be entirely healthy, it was killed and its vital 
organs examhied. In many cases the kidneys showed signs 
of degeneration, due undoubtedly t(j the fact that most 
preservatives must be eliminated through these organs. It 
is somewhat alarming to learn that, while apparently in 
good health, a vital organ can slowly become diseased from 
the food eaten. 

Experiments on human beings. Very extensive experi- 
ments have been carried out on human beings. While a 
few of these have been conducted on children or invalids, 
most of them have been carried out on healthy young men. 
In some of these experiments no ill effects have been noted, 
while in others, loss of appetite and weight, headache, and 
nausea have been observed. The most careful and exten- 
sive investigations of this khid are behig carried out by the 
Referee Board of the United States Department of Agri- 
culture. Three separate squads of young men have been 
experimented upon by being fed with food containing ben- 
zoate of soda. No evidence of disturbance of the digestion 
was discovered. The assimilation of the food, as well as the 
elimination of waste products, was entirely normal. The 
board concluded that 4 gm. of benzoate of soda per day 



peeservatio:n^ of foods 137 

could be consumed with the food without harm. No experi- 
ments on children were conducted by the board. In view 
of the results of previous experiments, it is quite possible 
that the immature or aged may suffer from the consumption 
of a preservative, while vigorous young men might be un- 
affected. Even though the preservative itself is entirely 
harmless, foods prepared with it may be unwholesome and 
inferior to foods prepared without it, so that it might be 
desirable to prohibit its use. 

The action of preservatives toward bacteria is of interest 
and importance. Among the large number of bacteria which 
gain entrance into foods, only a few give rise to the disagree- 
able taste and odors which we associate with decomposing 
foods. Substances have been selected as food preservatives 
on account of their ability to preserve the natural taste and 
odor of foods, and not for their ability to prevent the growth 
of bacteria in general. Direct experiments upon this point 
have sliown that the action of preservatives on bacteria is 
selective ; that is, the growth of some species is retarded far 
more than that of other species. The bacteriological exami- 
nation of preserved and unpreserved foods has shown that 
when a disagreeable odor and taste begin to appear, the 
preserved contain a much larger number of bacteria than 
the unpreserved. In other words, the preservatives prevent 
the growth of bacteria which produce the foul odors and 
taste, and allow other bacteria to grow at a rapid rate. In 
round numbers, the preserved foods can contain about four 
times as many bacteria as the unpreserved before seeming 
to be spoiled. 

Danger of consuming large numbers of bacteria. A con- 
siderable amount of evidence has been produced to show 
that even in the absence of any specific disease germs, the 
consumption of foods containing a large number of bacteria 



138 PUEE FOODS 

increases the death rate. This has been repeatedly shown 
with pubhc water suppUes. If the bacteria content is re- 
duced by filtration or other means, not only is there a reduc- 
tion in the death rate, due to typhoid and other diseases 
known to be caused by water-borne bacteria, but the death 
rate due to other diseases is also materially reduced. The 
same result has been repeatedly observed with milk. The 
death rate amono^ children is reduced when milk containinof 
a smaller number of bacteria is used. It would appear, 
therefore, that the use of preserved food is a menace to 
public liealth because such foods may be consumed while 
swarming with bacteria. 

Preservation of decomposed foods. Another very impor- 
tant question is Avhether the use of preservatives renders 
it possible for manufacturers to use inferior or decomposed 
foods. Formaldehyde has been used to a considerable ex- 
tent to deodorize eggs which were too badly decomposed 
to be sold. For this purpose the eggs are broken, the shells 
removed, and the liquid treated with formaldehyde. This 
practice has been very largely stopped by the liealth officers. 
Sulphites have been very largely used in the preparation of 
sausage meat or Hamburg steak from the trimmings and 
odd ends whicli accumulate in the meat shops. These scraps 
must not be allowed to become too much tainted or the sul- 
phite will not remove the odor. It is very effective, how- 
ever, in restoring the bright red color to meat which has 
become dark. On chopping such meat and adding the 
sulphite a very attractive sausage meat can be produced. 
Especially when it is exposed to the air the meat acquu-es 
a bright red color. 

Preservatives vs. cleanliness. Takuig human nature as 
it is, it would seem that the use of preservatives would 
not lead to the adoption of the most sanitary methods of 



PRESERVATION OF FOODS 139 

handling foods. Foods could be kept by the aid of pre- 
servatives quite as long, even though strict cleanliness were 
not observed. When we remember that bacteria will grow 
most luxuriously in the presence of preservatives, the foods 
handled in this way cannot but be dangerous to health. One 
of the strongest reasons why the catsup manufacturers de- 
sire to use preservatives is that they have been accustomed 
to handle and keep tomato pulp in bulk until it is con- 
venient to work it up into catsup. The finished product is 
also sold in barrels to restaurants, Avhere it is put in con- 
venient receptacles for the table until the stock is exhausted. 
There is no question but that the liability to contamination 
of the catsup under these conditions is very great. A very 
thorough overhauling of the process would be necessary if 
the use of preservatives were prohibited. While benzoate of 
soda has been found to be harmless in the amounts used m 
foods when consumed by healthy adults, the evidence at 
hand with reference to the other chemical preservatives 
would lead to the conclusion that the consumption of foods 
containing them is attended with more danger, especially 
smce the most sanitary methods may not have been nsed 
m the preparation of the food. It is of the greatest impor- 
tance that the statement be made on the label of foods that 
they contain a given preservative, in order that consumers 
may avoid such foods particularly when in poor health from 
organic diseases, especially of the kidneys. 

Hydrogen peroxide. These general statements about pre- 
servatives do not apply to hydrogen peroxide. This com- 
pound decomposes very quickly when added to foods. The 
decomposition products are oxygen and water. The oxygen 
serves to destroy the bacteria present. 

Preservatives do not sterilize foods. The statement has fre- 
(|uently been mad^ that the consumption of foods containing 



140 PUEE FOODS 

preservatives is accompanied with less risk because the pre- 
servative will kill bacteria which are present. This state- 
ment is by no means correct, as preservatives are never 
added in sufficient amount to sterilize foods. In the amount 
used they simply retard the growth of the bacteria, espe- 
cially those which produce the disagreeable odor and taste 
in decomposed foods. So that there can be present m foods 
containing preservatives a very much greater number of 
bacteria, before they emit any disagreeable odor or taste, 
than is possible with foods containing no preservatives. 
Sterilization with heat, on the other hand, absolutely de- 
stroys bacteria which may be present, and is therefore a 
much safer method of preservation of foods. 



CHAPTER XTII 

FRUITS, JAMS, AND JELLIES 

Composition of fruits. Fruits are composed very largely 
of water, containing on the average 80 to 90 per cent. Most 
of the other constituents are held in solution by this water. 
The solids are composed of sugars, gums, organic acids, 
starch, a small amount of cellulose, mineral matter, and 
aromatic substances such as essential oils and compound 
ethers. A small amount of coloring matter is also present. 
Chlorophyll gives the green color, xanthophyll the yellow 
color, and erythrophyll the red. The other shades are pro- 
duced by a combination of these fundamental colors in vary- 
ing proportions. With the exception of the mineral matter, 
all of these substances are carbohydrates ; that is, they are 
composed of carbon, hydrogen, and oxygen. The carbon is 
obtained from the carbon dioxide of the air, which is decom- 
posed by the plant with the aid of sunlight, giving off free 
oxygen. The oxygen and hydrogen are obtained mainly 
from water. The mineral constituents are obtained from 
the soil, being carried to the plant in solution in water. 

Changes in composition during ripening. Fruits in the 
green state contain a large amount of starch, which is con- 
verted into sugar as the fruit ripens. The amount of sugar 
hi some ripe fruits is very large. Grapes may contain as 
much as 25 to 30 per cent, apples 5 to 15 per cent, and 
such sweet fruits as peaches and pears almost as much as 
this. This is another instance in which plants exhibit the 
ability to change the insoluble carbohydrate, starch, into 

141 



142 



PURE FOODS 



sugar. Starch is a very convenient and stable form in 
which the plant can store nourishment for future use. 
When fruits decay or their juices are allowed to ferment, 
the sugar undergoes another transformation by which al- 
cohol is produced. In this manner cider and wine are 
made. Tlie following table shows the transformations which 
take place during the growth and ripening of apples. 

TABLE XXIII 
Composition of Apples at Various Stages of Growth 





Very green 


Green 


llipe 


Overripe 


Average for 
American apples 




Pel' cent 


Per cent 


Per cent 


Per cent 


Per cent 


Total solids . . 


18.47 


20.19 


19.64 


19.74 




Cane sugar . . 


1.63 


4.05 


6.81 


5.26 


3.40 


Invert sugar . . 


6.40 


6.46 


7.70 


8.81 


7.90 


Starch .... 


4.14 


3.67 


0.17 






Malic acid . . 


1.14 




0.65 


0.48 





This table shows very clearly how the large amount of 
starch in green apples gradually becomes converted into 
sugar. Taken in connection with the disappearance of a 
large portion of the malic acid, the great difference in taste 
between the green and the ripe apple is accounted for. A 
similar transformation takes place in the apples wdiich are 
stored for consumption during the w inter. In the fall the 
apple is hard and tasteless because it contams a large 
amount of starch. In the spring it is mellow and sweet 
because the starch has been converted into sugar. The 
green apple is indigestible because of its large content of 
starch, which cannot be digested in the raw state. No ill 
results follow if such apples are cooked before they are 
eaten, although they still contain a large amount of acid. 



FRUITS, JAMS, AND JELLIES 143 

The acids found in fruits are quite similar to eacli other. 
They are all organic acids, being composed of carbon, 
hydrogen, and oxygen. They can therefore be oxidized in 
the human system so as to liberate their energy. Most of 
these acids are white solids. Besides malic acid, which is 
found in apples, citric acid found in lemons and oranges, 
and tartaric acid found in grapes, are typical of this class 
of substances. Citric and tartaric acids are separated in 
large quantities for various purposes. 

Cream of tartar. Tartaric acid is present in grapes in 
the form of the acid salt of potassium, which is known as 
cream of tartar. It is obtained in large quantities in the 
process of making wine. When the juice is pressed out of 
the grapes, most of the cream of tartar is present in the 
expressed juice, while a small portion remains in the solid 
portion of the grape, known as pomace. When the grape 
juice is fermented and the sugar converted into alcohol, 
the cream of tartar crystallizes out because it is insoluble 
in alcohol. It settles out on the bottom of the Avine casks 
and is known in this crude state as argols or lees. Large 
quantities of this product are imported from Italy and 
France and refined in the United States. The cream of 
tartar is first dissolved in water, the solution filtered and 
allowed to crystallize. The brown crystals are again dis- 
solved, the impurities precipitated and filtered out, and the 
solution clarified by filtration through bone black, after 
which pure white crystals are obtained. These are pow- 
dered and used in making baking powder and also sold 
as cream of tartar. 

Tartaric acid. If tartaric acid is desired, the potassium 
must be removed from the cream of tartar. This is done 
by the addition of sulphuric or phosphoric acids, which 
combine with the potassium, after which the tartaric acid 



144 PUEE FOODS 

may be crystallized out. It is purified by recrystallization 
in the same manner as the cream of tartar. Both of these 
compounds are used in the manufacture of baking powder. 
Cream of tartar lias acid properties because it contams only 
half the amount of potassium necessary to neutralize the 
tartaric acid. 

Citric acid. This acid is prepared from the juice of lemons, 
the rinds being pressed for their essential oil. By far the 
greatest quantity is produced in Sicily, and smaller quanti- 
ties in other localities where the fruit grows abundantly.- 

Mineral matter. Fruits contain a fairly large amount of 
mineral matter, as has already been sliown. Grapes contain 
a considerable amount of potassium in combination with 
tartaric acid. Calcium, iron, aluminium, phosphorus, and 
manganese are also present in small amounts. These min- 
eral constituents of fruits are in excellent condition for 
digestion and absorption by the system. Tlieif cannot he 
ahsorhed when taken in pnre form^ but must first be com- 
bined with organic matter. This the plant does in produc- 
ing the fruit. Inorganic salts of the metals are assimilated 
only to a slight extent. 

Flavor of fruits. The characteristic flavor of fruits is 
produced by very small quantities of compounds known as 
compound ethers or ethereal salts. One of the simplest of 
these is ethyl acetate. It may be easily produced from 
acetic acid and ordinary alcohol, which is called by chem- 
ists ethyl alcohol. By warming these two substances with 
concentrated sulphuric acid they combine to form ethyl 
acetate, which may be purified by distillation. It is a color- 
less mobile liquid of a pleasant fruity odor. Amyl acetate 
may be produced in a similar manner from amyl alcohol 
and acetic acid. It is known as banana oil. Its odor is 
very similar to that of ripe bananas. Amyl valerianate is a 



FKUITS, JAMS, AND JELLIES 



145 



compound of amyl alcohol and valerianic acid, and has an 
odor very similar to that of apples. Tlie odor of few if an}^ 
fruits is produced by a single substance, but is generally 
due to the presence of several ethers. Artificial fruit flavors 
are made by combining several of these compounds, and 
often resemble in odor very closely the natural fruits. 

Pectin. Another constituent of fruits, which causes the 
juices to solidify into jelly when boiled with sugar, is known 
as pectin or pectose. It is a carbohydrate and produces a 
jelly only in the presence of a definite amount of acid, five 
tenths per cent seeming to be the amount most favorable 
to the formation of a good jelly. ^ 

The following table gives the composition of a number 
of our common fresh fruits : 

TABLE XXIY 
Composition of Fresh Frttits 



Fruit 


Water 


Total 
sugar 


Protein 


Aci.l 


Ash 


Calories 




Per cen t 


Per cent 


Percent 


Per rent 


Per cent 




Apples .... 


85.4 


11.27 


0.04 


0.70 


0.27 


200 


Bananas . . . 


73.8 


21.7 


1.17 


0.30 


0.5 


400 


Blackberries . . 


80.3 


10.0 


1.3 


0.77 


0.5 




Cranberries . . 


88.0 


0.0 


0.4 


2.34 


0.2 


215 


Grapes . . 


80.12 


10.50 


1.20 


0.50 


0.5 


450 


Huckleberries . 


8L9 


10.50 


0.0 




0.3 


345 


Lemons .... 


88.0 


0.37 




5.30 




205 


Oranges . . . 


80.0 


5.05 




1.35 




240 


Peaches . . . 


88.0 


10.8 


0.7 


0.50 


0.7 


190 


Pineapples . . 


85.10 


12.22 


0.48 


0.77 


0.42 




Plums .... 


78.4 


13.25 


0.4 


1.00 


0.52 


395 


Strawberries 


00.0 


7.00 


0.0 


1.10 


0.0 


180 


Raspberries . . 


84.0 


12.0 


1.7 


1.48 


0.0 


310 



N. E. Goldtliwaite, Jour, of Ind. amlEng. Chem., Vol. I, p. 3o3. 



146 . PURE FOODS 

The delicious flavor of most fruits is due to the combi- 
nation of the sweet taste of the sugars dissolved in the 
water of the fruit, to which the acid gives an agreeable 
contrast, and the essential oils and ethers which give the 
characteristic fruit flavor and aroma. The natural varia- 
tions in the amount of sugar and acid, as well as essential 
oils and ethers present in different fruits, are sufficient to 
suit all tastes and personal idiosyncrasies. 

Food values of fruits. It will be observed that bananas 
have the greatest food value among fruits on account of 
the large percentage of sugar. Grapes are very nearly 
as rich in this constituent. While the percentage of pro- 
tein is apparently small, it is quite appreciable in propor- 
tion to the total solids, of which the protein constitutes 
from 2 to 10 per cent. The fruit acids constitute a still 
larger proportion of the total solids ; that is, from 1 to 
45 per cent. 

Fresh fruits constitute good summer diet. On account of 
the small calorific value, a diet of fruits would not be very 
nourishing unless a very large amount Avere consumed. 
For this reason they are admirably adapted to be the food 
of people living in tropical countries, and as a summer 
diet when a high calorific value is unnecessary. The acid 
present in fruit is also desirable during the summer, 
although in some cases it acts injuriously. In eating raw 
fruits there is some danger from bacteria adhering to the 
surface, especially when the fruit has been exposed for 
sale on a dusty street. 

Preserved fruits constitute good winter diet. While fresh 
fruits form a most desirable food for the summer, preserved 
fruits, especially jams and jellies, are well adapted for con- 
sumption during the winter, on account of the high calo- 
rific value produced by the large amount of sugar which 



FRUITS, JAMS, AND JELLIES 147 

has been added, constituting generally at least 50 per cent 
of the preserved fruit. The calorific value of dried fruits 
is also higher than that of fresh fruits because most of the 
water has been expelled. 

Cold storage of fruits. As has already been stated, every 
method of preservation must kill the bacteria present or 
retard their growth and activity. Cold storage is well 
adapted to the preservation of fruits, provided the temper- 
ature is not allowed to fall below the freezing point. 
Many fruits may be kept in excellent condition by this 
method for six to nine months, so as to be quite as palat- 
able as the fresh fruits. 

Dried fruits. Preservation of fruits by drying has been 
practiced for centuries. Until recently very little improve- 
ment has been made over the primitive method of drying 
in the sun. The modern preservatives have been used to 
prevent the formation of mold during the drying process. 
Sulphurous acid has been most largely used, because the 
fruit containing it does not darken during the drying proc- 
ess. The fresh fruit is exposed to tlie fumes of burning 
sulphur before being placed on the drying frames. While 
some of the sulphurous acid escapes with the moisture, a 
considerable amount always remains and is consumed with 
the fruit. In this manner the so-called evaporated apples 
are produced, which are perfectly white, without a trace of 
darkening. 

Desiccated fruits. The necessity of using preservatives 
is entirely obviated when a method of drying, recently de- 
vised, is employed. Air which has been artificially deprived 
of its moisture and then heated is passed over the fruit. 
The moisture is taken out so rapidly that molds and bac- 
teria cannot grow. ,The dried fruit may be kept indefinitely 
without decomposition. On moistening with water the 



148 



PURE FOODS 



fruit regains its flavor and bulk. This method of drying is 
superior in many Avays to the older processes. 

Canned fruits. Preservation by means of heat involves 
cooking the fruit. In some cases this is an advantage 
because the fruit is made more digestible. This method 
cannot be used with some fruits because the flavor is de- 
stroyed by cooking. In all cases, after sterilization, the 
entrance of bacteria must be prevented. This is generally 
accomplished by sealing in an an-tight container. The ex- 
clusion of the air is not essential to the preservation of the 
fruit. It would keep quite as well if placed in a bottle 
closed with a plug of cotton. The cotton keeps out bac- 
teria, because the latter are found on particles of dust 
which are sifted out by the cotton. 

Jams and jellies. Fruits are also preserved by boiling 
witli sugar. If tlie whole fruit is used, jam is produced. 
As most of the nutriment of fruits is in solution in the 
juices, the composition of jams and jellies is very similar. 
The portion discarded in making jelly is quite indigest- 
ible. The following table gives the composition of jams 
and jellies : 

TABJ.E XXV 

Composition of Jams 



Fruit 


Solids 


Reducing 
sugar 


Cane 
sugar 


Total 
sugar 


Acid 


Protein 


Ash 




Per cent 


Percent 


Per cent 


Per cent 


Percent 


Percent 


Per cent 


Apple . . . 


63.22 


25.52 


29.11 


54.63 


0.28 


0.18 


0.20 


Blackberry . 


55.42 


18.77 


29.00 


47.77 


0.85 


0.74 


0.48 


Grape . . . 


56.64 


.33.44 


11.33 


urn 


0.74 


0.53 


0.74 


Pear . . . 


61.52 


13.20 


.33.74 


46.94 


0.16 


0.31 


0.28 


Peach . . . 


65.65 


36.48 


23.16 


59.64 


0.5 






Plum . . . 


50.43 


28.29 


9.70 


38.00 


1.01 


0.53 


0.54 


Pineapple . 


73.92 


14.05 


46.40 


60.45 


0.32 


0.31 


0.30 



FRUITS, JAMS, AND JELLIES 



149 



TABLE XXVI 

Composition of Jellies 



Fruit 


Total 
solids 


Reducing 
sugar 


Cane 
sugar 


Total 
sugar 


Acid 


Protein 


Ash 




Per cent 


Per cent 


Percent 


Per cent 


Percent 


Per cent 


Per cent 


Apple . . . 


59.18 


20.78 


33.04 


53.82 


0.28 


0.18 


0.22 


Blackberry . 


59.63 


12.51 


44.90 


57.41 


0.48 


0.24 


0.33 


Crab apple . 


03.28 


34.93 


23.68 


58.61 


0.17 


0.14 


0.11 


Grape . . . 


63.66 


32.29 


30.52 


62.81 


0.52 


0.18 


0.45 


Huckleberry 


63.02 


24.27 


32.74 


57.01 


0.25 


0.07 


0.28 


Orange . . 


68.56 


3.95 


62.52 


65.47 


0.17 


0.42 


0.30 


Peach . . . 


69.98 


8.75 


56.59 


65.34 


0.25 


0.18 


0.21 


Fear . . . 


69.12 


6.58 


58.46 


65.04 


0.18 


0.16 


0.34 


Pineapple . 


80.28 


22.13 


56.70 


78.83 


0.33 


0.39 


0.43 


Plum . . 


45.56 


19.18 


22.67 


41.85 


1.13 


0.35 


0.68 


Mixed fruit . 


66.58 


39.17 


24.22 


63.39 


0.37 


0.07 


0.21 



Food value of jams and jellies. The amount of sugar iii 
these foods is about 50 per cent. Only a portion of it is 
present as cane sugar, because a considerable portion of the 
sugar added has been hydrolyzed by the acid of the fruit 
during the boiling. A portion of the reducmg sugar is that 
naturally present m the ripe fruit. As the percentage of 
total solids is very large, these foods are very concentrated 
and can give a large amount of energy. The fruit flavor, 
acid, and color make them very palatable foods. 

Jelly making. Jellies are characterized by a peculiar 
consistency, which may be described as a solid of very slight 
strength. While the jelly retains the shape of the mold in 
which it is cooled, it can hardly support its own weight. 
The constituents of fruits which cause them to '' jell " are 
pectin and acid. Almost all fruits contain the requisite 
amount of pectin, but many of the sweet fruits, such as 
peaches, blackberries, pears, etc., contain too little acid. 



150 PURE FOODS 

For this reason, jelly may be made from these fruits if they 
are used before they are fully ripe. Tlie fruit juice must 
contain about |- per cent of acid and 1 per cent of pectin. 
As most fruits contain a sufficient amount of pectin, failure 
to obtain a jelly is generally due to the absence of the 
requisite amount of acid. This may be introduced by add- 
ing tartaric acid, or, what is perhaps more satisfactory, the 
juice of a strongly acid fruit may be mixed with that of a 
sweet fruit. The fruit juice must be boiled with the sugar 
long enough to hydrolyze a portion of the latter, but not 
long enough to convert all of the cane sugar into reduc- 
ing sugars. The proper conditions are reached Avhen the 
boiling point is about 103° C. and the specific gravity of 
the hot mixture is 1.28.^ The proper proportion of sugar 
is also important and varies slightly with different fruits. 
All bacteria are killed during the boiling of the jelly. 
By pouring melted paraffin over the solidified jelly the 
entrance of more bacteria is effectually prevented. The 
growth of any bacteria which may gain entrance is very 
slow in the highly concentrated sugar solution. 

Artificial jellies. It has been assumed in the preceding 
discussion that fruit juice and sugar are the only constit- 
uents necessary for the preparation of jams and jellies. As 
made in the household, tliis is true. The food market has 
been flooded with jams and jellies which have been manu- 
factured in large quantities by very different methods. 
Instead of the various fruit juices, apple juice, together 
with an artificial flavor and color, has been substituted. 
The apple juice would give the necessary pectin, while the 
added color and flavoring matter would suggest the fruit 
whose jelly was imitated. In some cases the fruit flavor is 
obtained by using apple juice mixed with a small quantity 

1 N. E. Golclthwaite, Jour, of Inch and Eng. Che)a., Vol. I, p. 333. 



FllUITS, JAMS, AND JELLIES 151 

of the fruit Avhose flavor is desired. A cheaper jelly is 
obtained by using gelatin without any fruit juice at all, 
even that of the apple being omitted. The slightly acid taste 
of fruit jellies is obtained by the addition of organic acids, 
such as tartaric and citric ; although at times mineral acids, 
such as sulphuric or muriatic, have been employed. In such 
artificial jellies glucose has been largely used in place of 
sugar, the sweet taste being given by saccharin. Artificial 
coloring and fiavoring matter complete the deception. That 
tlie consuming public can be easily deceived is shown by 
the fact that large quantities of such artificial jelly has 
been sold under a variety of labels, such as currant, rasp- 
berry, strawberry, etc., Avlnle the contents of tlie jars was 
identical in every respect, no attempt being made to vary 
the color or flavor. 

Wholesomeness of artificial jellies. These artificial jellies 
have generally contained no injurious constituents except 
tlie mineral acids and poisojious coal-tar dyes or artificial 
flavors. The apple juice, glucose, and gelathi are substances 
of recognized food value. The fraud practiced on the public 
is largely one of deception. The protection afforded by 
pure-food laws has been the exclusion of poisonous con- 
stituents and the prohibition of the use of deceptive labels, 
making it illegal to sell as a fruit jelly a compound of 
gelatin, glucose, aniline dye, and artificial flavoring matter. 
If the ingredients are wholesome foods, a label stating the 
contents of the compound is a suflicient protection to the 
purchaser. 

Adulterated jams. In a similar manner, jams are con- 
sidered to be a product made by boiling fruits with sugar. 
A common practice with dishonest manufacturers has been 
to make jams out of the fruit pulp from which the juice 
has been expressed for the purpose of making jelly. By 



152 PURE FOODS 

cooking with sugar or glucose, and, if necessary, adding an 
acid, coloring matter, and artificial flavoring matter, a prod- 
uct would be obtained which could with difficulty be dis- 
tinguished, without a chemical analysis, from genuine jam. 
Most of these jams, as well as the artificial jellies, would be 
preserved with a chemical preservative as a cheaper method 
than careful sterilization and sealing of the jars. 

EXPERIMENTS 

27. Testing fruits for starch. Test green fniits, such as apples, 
pears, bananas, etc., for starch by applying a few drops of iodine 
solution to the freshly cut surface. If the bhie color does not develop, 
scrape off a little of the fruit with a knife and treat with boiling 
water. Allow to cool and repeat the test. Repeat the test with 
ripe fruit. 

28. Testing fruits for pectin. Prepare samples of the juices of both 
green and ripe fruits of various kinds, such as apple, j)each, currant, 
etc. The fruit should first be crushed, then warmed and strained 
through cloth. Place 5 ccm. of each sample in a test tube, add an 
equal volume of alcohol, shake, and allow to stand. The gelatinous 
precipitate which settles out in each case is the pectin of the fruit. 
A considerable difference in amount and character of the precipitate 
will be noticed. 

29. Acidity of fruit juices. The acidity of the fruit juices prepared 
in Experiment 28 is determined in the following manner : A small 
portion of the fruit juice is diluted with ten times its volume of dis- 
tilled water, and, while stirring, a dilute solution of caustic soda (see 
Experiment 14) is added drop by drop until a decided change of 
color is noted. By testing with red and blue litmus paper it will be 
found that at the point when the solution changes from acid to 
alkaline a decided change of color occurs. The litmus paper is dyed 
with a vegetable color, which is red in acid solution and blue in 
alkaline solution. A large number of other vegetables contain color- 
ing matter, which undergoes a decided change when the acid j^resent 
is neutralized with a base. 

Having noted the change in color at the point where all the 
acid is neutralized, measure out exactly 10 ccm. of the fruit juice, 



FRUITS, JAMS, AND JELLIES 153 

dilute with 100 ccm. of distilled water, and titrate with fifth-normal 
or tenth-normal caustic soda solution (see Experiment 14) until the 
color change is observed. Calculate the per cent of acid present. 
For this purpose 1 ccm. of fifth-normal caustic soda is equal to 
0.01 gm. of acid. If 5 ccm. of soda were used for 10 ccm. of the juice, 

the i>er cent of acid would be five tenths (' = 0.5 ). 

As some fruit juices contain very little natural color, it will be 
necessary to use litmus or some other indicator to ascertain when 
enough caustic soda solution has been added. Litmus paper may be 
used or a solution of the dye, or, still better, a solution of methyl 
orange. This indicator is prepared by dissolving J^ gm. of the dye 
in 100 ccm. of water. Only a few drops of this indicator should 
be added to the solution of the fruit juices. 

When the acidity of the fruit juices has been ascertained, experi- 
ments may be carried out to determine the jelly-making properties 
of the juice. The nature and amount of the pectin present will also 
be found to be of importance for this purpose. Equal portions of 
the juice and sugar are boiled and set aside to cool. If the acidity 
of the juice is high, a portion of the acid may be neutralized by the 
addition of measured volumes of the caustic soda solution, while if 
the juice is deficient in acid, citric, malic, or tartaric acid, or some 
strongly acid fruit juice, may be added. Experiments may also be 
made by varying the proportions of sugar and juice. 

30. Testing for fruit juices. The colors obtained when the acid 
of various fruit juices is neutralized are quite different, and charac- 
teristic with different fruits. A considerable amount of organic 
matter is also present in fruit juices, w^iich is precipitated with lead 
acetate and can be used to identify natural fruit juices. A solution 
of basic lead acetate has been found to combine the alkalinity with 
the soluble lead necessary to give both of these reactions. The 
solution is made as follows : 18 gm. of lead acetate are dissolved 
in 70 ccm. of hot distilled water and 11 gm. of lead oxide added. 
The mixture is boiled for half an hour with occasional stirring, after 
which it is allowed to settle for a few minutes and is then filtered. 
Enough distilled water is added to make the volume about 81 ccm. 
The solution must be kept in well-stoppered bottles. A dilute solu- 
tion made by adding about four volumes of water to one volume of 
the strone- solution will be found suitable for the following tests : 



154 PURE FOODS 

Place equal portions of the fruit juices prepared in Experiment 
28 in test tubes and add the lead subacetate solution until no further 
precipitate or change in color is produced. Note carefully the color 
changes and character of the precipitates obtained from these pure 
fruit juices. 

Test commercial samples of jams and jellies as follows : Add 
equal volumes of water, warm, and stir until a homogeneous solution 
is obtained, and filter. Test the filtrates with the lead subacetate 
solution. 

31. Testing for aniline dyes. As most artificial jams, jellies, and 
other fruit products are colored with aniline dyes to imitate the 
natural product, the test for the dyes gives good evidence of the 
character of the products. The test is carried out as follows : White 
woolen cloth is cut into narrow strips and freed from grease by boil- 
ing in very dilute caustic soda solution for about ten minutes. The 
soda is then washed out by boiling in water. The cloth is then dried 
and preserved for use. 

About 15 gm. of the fruit product are dissolved in 100 ccm. of 
distilled water, and then filtered if necessary. A few drops of dilute 
hydrochloric acid are added, and the solution again filtered if neces- 
sary. Strips of the woolen cloth are placed in the solution, which is 
boiled for five to ten minutes. The cloth is removed and washed 
in water and boiled in very dilute hydrochloric acid. The coloring 
matter naturally present in fruits generally imparts a dull color to 
the cloth, while aniline dyes produce bright shades. 

As a further test the color is dissolved by boiling the cloth in a 
dilute solution of ammonia made by adding a few drops of strong 
ammonia to 25 ccm. of water. When no more solvent action is ob- 
served, the cloth is removed, the solution is made "acid, and a fresh 
piece of M^oolen cloth boiled in the solution. If the second j)iece of 
woolen cloth is dyed, aniline dyes are present. 

Frequently with whole fruit like cherries the coloring matter is 
present in the solid particularly. When this is the case, the liquor 
should be drained off and the finely divided fruit warmed with three 
times its bulk of alcohol until the color is sufficiently extracted. 
The mixture is then filtered, and after diluting the filtrate with 
twice the volume of water and acidifying with hydrochloric acid, the 
wool is dyed as already directed. 



CHAPTER XIV 

FRESH AND CANNED VEGETABLES 

Composition of vegetables. Vegetables are very similar 
in composition to fruits. They contain about the same per- 
centage of water and solids and have the same calorific or 
energy value. They differ from fruits in that the main 
constituent is starch, while sugar is the most important 
constituent of fruits. For this reason, vegetables must, as 
a general rule, be cooked before being eaten, Avhile ripe 
fruit may be eaten raw. If vegetables are baked, the starch 
is to a greater or less extent converted into sugar, giving a 
sweeter taste. Vegetables are more easily stored and kept 
in good condition because starch is a very stable substance. 
If they are allowed to sprout, however, the starch is rap- 
idly converted into sugar and the vegetable soon decays. 
Vegetables also differ from fruits in containing little or 
no acid, but decidedly more mineral matter. The table 
on page 156 gives the composition of a number of common 
vegetables. 

Water in vegetables. In spite of its name, watermelon 
does not contain the largest percentage of water. Aspara- 
gus, lettuce, celery, and pumpkins contain a larger percent- 
age, while cucumbers contain the largest amount of this 
constituent. Corn, peas, and potatoes contain the least 
proportion of water, and therefore are the most nourishing 
of vegetables. 

Adulteration of vegetables. There is very little opportu- 
nity for fraud or* adulteration in the sale of vegetables, as 

155 



156 



PUEE FOODS 



TABLE XXVII 
Composition of Vegetables 



Vegetable 



Asparagus . . 

Beans . . . . 

Beets . . . . 

Cabbage . . . 

Carrot . . . . 

Celery . . . . 

Corn . . . . 

Cucumber . . 

Lettuce . . . 

Onion . . . . 

Parsnip . . . 

Peas . . . . 

Potatoes, Irish . 
sweet 

Pumpkins . . 
Watermelon 



Water Starch Sugar Protein Ash Caloi 



Per ceil t 
93.6 
87.23 
88.47 
90.52 
88.59 
94.50 
73.00 
95.09 
93.63 
87.55 
80.34 
79.93 
75.00 
70.27 
93.39 
91.87 



Per cen t 

2.55 

7.52 

7.94 

3.85 

7.56 

3.5 

13.50 

1.83 

2.18 

9.53 

16.09 

13.30 

19.87 

24.00 

3.93 

6.65 



Per cen t 



6.00 



0.77 
6.81 



Per cent 
1.83 
2.20 
1.53 
2.39 
1.14 
1.25 
5.00 
0.81 
1.41 
1.40 
1.35 
3.87 
2.00 
2.41 
0.91 
0.40 



Per cent 
0.67 
0.76 
1.04 
1.42 
1.02 
0.60 
0.70 
0.46 
1.61 
0.57 
1.03 
0.78 
1.00 
1.14 
0.67 
0.33 



105 
195 
215 
145 
210 
85 
470 
85 
90 
225 
300 
465 
400 
570 
125 
150 



they are generally sold in their natural state. Canned vege- 
tables may contain deleterious ingredients. Canned aspara- 
gus and mushrooms are frequently bleached by means of 
sulphurous acid. The green color of canned peas, etc. is 
frequently preserved with copper sulphate. As this is a 
violent poison, only minute quantities can be taken with 
foods without danger. The sale of foods containing this 
coloring matter is permitted if the amount present is not 
excessive and its presence is stated on the label. 

Desiccated vegetables. It is possible, by means of recently 
improved methods of drying, to produce desiccated vege- 
tables, which, when soaked in water, regain the taste and 
other properties of fresh vegetables. If kept in a dry place, 
such desiccated vegetables will keep mdefinitely, and can 



FRESH AND CANNED VEGETABLES 157 

readily be transported, as they are very light on account 
of the absence of the large amount of water present in their 
natural condition. 

Catsup. This is a sauce made from tomatoes and various 
spices. A great variety of substances have been used in 
making some of the catsups which have been placed on the 
market. Turnips and other cheaper vegetables and corn 
meal have been substituted for the tomatoes, the red color 
being obtained by the addition of aniline dyes. When toma- 
toes have been used, they have commonly been preserved 
with sodium benzoate or otlier preservatives. Inferior or 
old tomatoes could be utilized by the addition of the pre- 
servative. Before the recent national Pure Food Law was 
enacted, practically all of the catsup sold contained a pre- 
servative. Since then methods have been developed for 
the preparation and marketing of tomato catsup without 
a preservative, sterilization by means of heat being substi- 
tuted. Such catsup cannot be sold in bulk, but must be put 
up in bottles and must be used within a short time of open- 
ing the bottle. 

EXPERIMENTS 

32. Testing for sulphur dioxide. Test canned asparagus, mush- 
rooms, or other light-colored canned vegetables for sulphur dioxide 
by the methods given in Experiment 22. 

33. Testing for copper sulphate. Canned peas, beans, or spinach 
may be tested for the presence of copper sulphate as follows : A few 
cubic centimeters of the liquid portion are acidified with hydrochloric 
acid and filtered. To the clear solution a few drops of barium chloride 
solution are added. A w^hite, finely divided precipitate, which settles 
slowly, indicates the presence of sulphuric acid, formed by the decom- 
position of copper sulphate. This test will frequently fail with all 
except spinach, because the vegetables have generally merely been 
dipped in a copper sulphate solution and then drained. 

From 2.5 to .50 gm. of the solid portion of the canned vegetable 
are placed in a pordfelain or platinum dish and heated gently. After 



158 PURE FOODS 

the moisture has been expelled the heat is increased until the mate- 
rial begins to burn. AVhen only charcoal remains, the dish is allowed 
to cool and the residue is moistened with not more than 3 ccm. of 
concentrated nitric acid and warmed for a few minutes. After adding 
25 to 50 ccm. of water the charred mass is well stirred and filtered. 
If copper sulphate has been used, the copper will be j)resent in the 
nitric acid solution. A portion of the solution is neutralized with 
ammonia and a slight excess added. If copper is present, the solu- 
tion will be blue. After observing the color, acetic acid is added until 
the solution is again acid, and a few drops of potassium f errocyanide 
solution are then added. A wine-red color indicates copper. 

The copper in the remainder of the nitric acid solution may be 
plated on platinum foil as follows : A few cubic centimeters of dilute 
sulphuric acid are added and a small piece of platinum foil is sus- 
pended by a platinum wire in the solution. Another platinum wire or 
foil is suspended in the solution, care being taken that it does not 
touch the first piece of platinum. The two wires are connected with 
an electric circuit in such a way that the platinum foil is attached 
to the negative wire of the circuit. Electric batteries or a direct 
electric-lighting circuit may be used. In a few hours the copper will 
be deposited on the platinum foil and may be easily seen by its 
red color. 

If all the nitric acid solution from a weighed amount of the canned 
vegetable is used, and the platinum foil is weighed before and after 
the copper is deposited, the amount of copper or copper sulphate in 
the vegetables may be ascertained. By multiplying the weight of 
copper obtained by 4, the weight of copper sulphate will be obtained. 
Although the copper was added as copper sulphate, it is not present 
as such in the vegetable, but is combined with the organic matter, 
presumably with the j^rotein. For further details on making the 
determination, the author's textbook, "Quantitative Chemical Anal- 
ysis," may be consulted. 

34. Testing for aniline dyes. Canned tomatoes or other canned 
vegetables which are suspected to have been colored with aniline 
dyes may be tested by the method given in Experiment 31. 



CHAPTER XY 

BREAD AND THE CEREALS 

Bread an ideal food. In many ways bread is an ideal 
food. It contains all the elements necessary to sustain life, 
although it is somewhat deficient in fat. For this reason 
it is generally eaten with butter or other food rich in fat. 
The physical form of bread is such that with proper masti- 
cation the digestive fluids readily penetrate the mass. It 
does not digest rapidly, but gradually, and thus meets the 
needs of the system for nourishment, without the necessity 
of eating frequently. Bread is classed as a staple food be- 
cause it can be consumed by all human beings without any 
ill effects. An exclusive diet of bread would, of course, 
become very distasteful, as the needs of the human system 
seem to be best met by a mixed and varied diet. 

Gluten. Bread can be best made only from wheat and 
rye flour, on account of the peculiar property of the gluten 
or protein of these grains. It has the property of absorbing 
nearly three times its weight of water and formmg a viscous, 
sticky, tough, and elastic mass. The carbon dioxide gas pro- 
duced by the action of yeast distends this elastic mass, which 
hardens during the baking and leaves the bread light and 
porous. As corn and other cereals cannot form such an 
elastic mass, they cannot be used for making bread. Wheat 
and rye contam a large percentage of protein, namely 10 
to 14 per cent, while Indian corn, barley, and buckwheat 
contain only from 7 to 9 per cent. As the nitrogenous con- 
stituent of foods is the most diflicult to produce and the 

159 



160 PURE FOODS 

most expensive, this larger percentage of protein in wheat 
gives it a decidedly greater value as a food. 

The following table gives the average composition of 
wheat flour: 

TABLE XXVIII 

Composition of AViieat Flour 

Per cent 

Protein or gluten 10-13 

Starch 75 

Fat 1-1| 

Ash or mineral matter \~\. 

Water . 10-12 

Grades of flour. The relative amounts of protein and 
starch vary with the kind of wheat and the soil and climate 
in Avhich the wheat is grown. The protein and starch are 
also unequally distributed in the grain, the percentage of 
protein being greatest near the hull and least in the center, 
where the percentage of starch is greatest. The various 
grades of flour on the market differ in composition not only 
because made from different grades of wheat, but also 
because made from different portions of the kernel of the 
wheat. The patent or middlings flour, which constitutes by 
far the largest part of the flour produced, contains less 
protein and ash and more starch than bakers' or family 
flour, of which only about one fourth as much is produced. 
The hulls of the grain constitute the bran, which contains 
0.8 per cent of mineral matter and as liigh as 15 per cent 
of protein, and is used as cattle food. 

Graham and whole-wheat flour. These flours contain the 
entire kernel of the wheat, and by bolting could be separated 
into bran, patent, and family flour. The percentage of ash 
or mineral matter, as well as protein, is therefore consider- 
ably higher than in the finer or bolted grades of flour. For 



BREAD AND THE CEKEALS 161 

this reason the claim has often been made that whole-wheat 
and Graham bread constitute a more nutritions diet than 
bread made from bolted flour. Careful dietary experiments 
have proved this idea to be erroneous. It has been shown 
that the system is unable to assimilate as large a proportion 
of the mineral and protein matter of whole-wheat flour as 
of the finer grades, so that from a given weight of bread the 
same amount of nourishment can be derived, whether made 
of bolted or unbolted flour. In addition it appears that the 
coarser particles of bran in the whole-wheat flour have an 
irritating effect in many cases on the delicate lining of the 
digestive tract. 

Bleached flour. Wheat flour is subject to some adulter- 
ation. Inferior grades of wheat flour are at times mixed 
with or sold as superior grades. This practice has become 
more common since the processes of bleaching flour have 
been introduced. The grade or quality of flour is largely 
determined by its appearance, odor, and color, as well as by 
its fineness, as indicated by rubbing between the fingers. A 
very minute amount of nitric oxide will remove the yellow 
tint of ?Ji inferior grade of flour, so that it can be sold as a 
much higher grade. The sale of bleached flour is therefore 
generally held to be illegal. The bread-making qualities of a 
sample of flour may be ascertamed by a test of the tenacity 
and elasticity of the dough produced from the flour. This is 
an important test in the hands of an experienced person. 

Mixed flour. Flour made from other grains is sometimes 
mixed with wheat flour. Corn and barley flour have been 
used as adulterants in this manner. These foreign flours 
are detected by a microscopic examination. The starch 
grains of wheat are circular and of two sizes, the larger 
having a diameter of 0.021 to 0.041 mm. and are marked 
with concentric * rings, while the smaller grains have a 



162 PURE FOODS 

diameter of about 0.005 mm. The starch grains of the 
other cereals are of a different size and appearance. 

Other flours than wheat. Flour made from other grains 
than wheat is less used and differs m composition from 
wheat flour to a considerable extent. Rye flour contains a 
larger percentage of protein, ash, and crude fiber than wheat 
flour. It is -also much coarser and makes a darker-colored 
bread. Indian corn flour contains only about 7 per cent of 
protein and a higher content of starch and fat than wheat 
flour. The protein does not form the tough elastic mass so 
characteristic of the gluten of wheat flour. Barley flour is 
similar in composition to corn flour but contains less fat. 
Buckwlieat flour con tarns a relatively large amount of fat 
and has only a small percentage of protein. 

The raising of bread. Bread is any baked mixture of any 
kind of flour and water with or without a leavening agent. 
By bread is generally understood that made from wheat or 
rye flour. While at times the dough is raised by a chemical 
substance, such as baking powder, the great bulk of the 
bread used is raised by means of yeast. Chemically the 
bread produced by means of yeast is slightly different from 
that raised by means of baking powder. A small percentage 
of soluble carbohydrates is present in flour and dough. The 
yeast acts on this material, converting it into alcohol and 
carbon dioxide gas, which becomes entangled in the gluten 
and, by expanding when heated, raises the bread. Although 
a portion of the alcohol escapes during the baking, fresh 
bread contains a small amount of alcohol. Baking powder 
does not bring about any decomposition of this kind. Dur- 
ing the process of baking, a small percentage of the starch 
is rendered soluble by being converted into dextrin and 
invert sugar, which gives a slightly sweet taste to the bread, 
especially the crust. 



BREAD AND THE CEREALS 163 

Water in bread. A common method of making cheap 
bread consists in introducing more than the normal amount 
of water. Well-made bread should contain from 33 to 40 
per cent of water. A poor quality of bread will contain 
from 40 to 48 per cent of water. Bread containing this 
amount of water tends to become moldy. Another com- 
mon method of defrauding the customer consists in selling 
light-weight loaves. The loaves on the market differ very 
much in weight, many of them being lighter than the 
standard pound weight. 

Adulteration of bread. Aside from adding too much 
water, using an inferior grade of flour, and making light- 
weight loaves, other adulterations of bread are rarely 
practiced. Gypsum, chalk, bone ash, and other mmerals 
cannot be added to bread without visibly affectmg its 
quality. The use of alum to improve the appearance of 
bread made from inferior flour is not very common. Sul- 
phate of copper has also been used to a limited extent for 
the same purpose. 

Adulteration of cake. Cake differs from bread chiefly in 
the addition of eggs, sugar, butter, spices, and flavoring 
matter. Some of these ingredients are subject to consider- 
able adulteration, while frequently very inferior grades are 
used in cake because the consumer has no means of judging 
the quality of the ingredients. Owing to the cost and diffi- 
culty of obtaining fresh eggs, the temptation is very great 
to use some form of preserved eggs. No objection can be 
raised to the use of cold-storage eggs in good condition, 
or a good grade of desiccated eggs. This cannot be said 
of the liquid eggs which have been used to a considerable 
extent. Such eggs have been broken and the liquid por- 
tion separated from the shells. By the addition of a pre- 
servative, such as borax or formaldehyde, such eggs could 



164 PURE FOODS 

be transported in open casks from China to New York. 
Eggs which have become so badly decomposed as to be 
unsalable could be rendered odorless by the addition of 
formaldehyde. Through the activity of the state and na- 
tional health authorities the sale of such eggs has been 
largely prevented. 

Egg substitute. The addition of the requisite number of 
eggs for a given cake is often entirely omitted and their 
absence masked by the addition of the requisite amount of 
some coloring matter. If a portion only of the eggs is 
omitted, enough coloring matter is added to give the color 
produced by the full number of eggs. This deception is 
possible because the consumer considers the yellow color 
evidence of the presence of eggs. Such yellow coloring is 
often sold under the name of '' egg substitute." 

Breakfast foods. The cereals are also consumed in large 
quantities in the form of breakfast foods. They differ very 
little in composition from the cereal from which they are 
made, liy various processes, such as steaming, roasting, or 
baking, the starch of the cereal is rendered more soluble 
and partially converted into sugar, so tliat the flavor is 
improved and the time required for cooking the breakfast 
food is materially reduced or cooking rendered entirely 
unnecessary. Individuality is also given to the various 
preparations by varying the size and general appearance 
of the grahis. 



CHAPTER XVr 

LEAVENING AGENTS 

Discovery of yeast. Bread is uiulou])tedly one of the 
foods which has been used for the longest time Vjy man. 
In the most primitive state of civihzation cereals of various 
kinds were crushed by means of flat stones or crude mills. 
The flour so made was mixed with water and baked on 
hot stoves into cakes. It was very early discovered that 
cakes which were allowed to remain for some time before 
baking were more porous and palatable, and that this ob- 
ject was still better attained by reserving a portion of one 
day's mixing to be kneaded into the fresh cake of the 
following day. 

The yeast plant. Although this process of leavening is 
of the greatest antiquity, it is less than a century since 
the nature of the process was at all understood. It is now 
known that leavened bread contains an enormous number 
of microscopic organisms known as the yeast germ or plant. 
When this plant grows and multiplies, it converts certain 
soluble carbohydrates into alcohol and carbon dioxide. This 
carbon dioxide gas remains entangled in the dough, so tliat 
when heat is applied it expands and causes the bread to rise. 
A common household method of making bread lighter con- 
sists in adding to the dough the water in which potatoes 
have been boiled. This method is effective because this 
water contains dissolved starch, which is acted upon by 
the yeast with the production of carbon dioxide. The same 
object is attained by the addition of a form of dextrose 

165 



166 PURE FOODS 

known as bakers' sugar. This is manufactured from corn- 
starch and is largely used by the bakers. 

Sour bread. If the dough is allowed to stand for too long 
a time or at an unsuitable temperature, another so-called 
ferment may become active and convert the alcohol into 
acetic acid, thus making the dough sour. We know now 
that the germs of these organisms are widely distributed in 
nature, so that, unless the greatest care is taken to exclude 
them, they will be present and set up fermentation in any 
suitable organic matter. It is for this reason that most foods 
rapidly become sour, especially during warm weather. 

Raising bread by means of carbon dioxide gas. Since the 
nature of the process of raising bread was made clear, many 
attempts have been made to supplant the old-fashioned 
method of raising bread by means of yeast, but so far these 
efforts have met with very little success. As bread is raised 
by the expansion of the imprisoned carbon dioxide gas, the 
attempt has been made to force this gas into the dough, 
which for this purpose was placed in steel cylinders. An 
attempt in London to sell bread made by this process did 
not succeed, because the bread differed in flavor from that 
raised with yeast. 

Liebig's method of raising bread. Attempts have been 
made to mix Avith the flour chemical substances which 
would gradually liberate the carbon dioxide gas necessary 
to raise the bread. The distinguished chemist Liebig sug- 
gested that a very suitable combination of this kind would 
be sodium bicarbonate and hydrochloric (muriatic) acid. 
By the interaction of these substances the carbon dioxide 
needed would be liberated, and there would also be formed 
some sodium chloride or common salt, which would be 
necessary in any case for the purpose of seasoning the 
bread. The difficulty in using this process is that it would 



LEAVENING AGENTS 167 

be necessary to have an acid of exact strength, and to 
measure the acid as well as the sodium bicarbonate with 
the greatest care, so that an excess of neither substance 
would be present. The ordmary cook or baker does not 
possess the mtelligence and skill necessary to do this. 

Cream of tartar baking powders. A number of other 
acids have been more largely used, sodium bicarbonate being 
in each case the substance employed to furnish the carbon 
dioxide gas. Acid potassium tartrate or cream of tartar 
has been quite largely used. Formerly these two substances 
were purchased separately and the proper quantities of each 
measured out and added to the flour before mixing the 
dough, the sodium bicarbonate being known as saleratus. 
The use of these substances separately has now been very 
largely superseded by the so-called baking powders. These 
powders are simply mixtures of sodium bicarbonate and a 
solid acid constituent like potassium bitartrate. When such 
a mixture is moistened with water, the acid acts on the 
bicarbonate of soda, liberating carbon dioxide and forming 
the sodium salt of the acid constituent. As the moisture 
of the air is slowly absorbed by the mixture, the baking 
powder would slowly lose its carbon dioxide and be re- 
duced in strength. In order to prevent this action, starch 
must be added to the mixture. 

Alum and phosphate baking powders. A number of other 
acid substances are used in baking powders, the most com- 
mon being acid calcium phosphate and alum. Sodium bicar- 
bonate must always be present, as well as starch, to prevent 
interaction between the constituents of the powder until it 
is moistened m the process of mixing the batter. The three 
classes of baking powder are known as tartrate, phosphate, 
and alum powders. They are about equally efficient as 
leavening agents, the constituents being combined in such 



168 PURE FOODS 

proportions that they exactly neutralize each other. Starch 
is added in a proportion sufficient to give powders of equiv- 
alent strength, so that a teaspoonful of any baking powder 
shall liberate the same amount of carbon dioxide. The 
various powders on the market differ somewhat in keeping 
qualities and also in the relative rapidity with which the 
carbon dioxide is liberated. These properties may be some- 
what modified by adding a small amount of tartaric acid to 
tlie tartrate powders, as well as by making mixed po.wders ; 
that is, using two acid constituents in the same powder. 

Objections to the use of alum baking powders. The use 
of alum baking powders has met with very considerable 
opposition on account of the poisonous properties of alum. 
For this reason the sale of baking powders containing 
alum lias been prohibited m some states. It is doubtful, 
however, if any alum is ever present in the stomach after 
bread or cake is eaten which has been prepared with a 
baking powder containing alum. This is due to the fact 
that when such powders are moistened, the alum is decom- 
posed by the sodium bicarbonate, with the liberation of 
carbon dioxide and the formation of sodium sulphate, 
potassium sulphate, and aluminium hydrate. While there 
is a possibility that by the action of the hydrochloric acid 
of the gastric juice these substances may again form alum, 
it is generally believed that this action does not take 
place to any great extent. The practice of adding alum to 
flour in order to produce a whiter bread is to be con- 
demned. The substitution of ammonia alum in place of 
the more expensive potash alum in the manufacture of bak- 
ing powders is also reprehensible. A great deal of baking 
powder is also made with sodium alum. 

Wholesomeness of phosphate and tartrate powders. No 
objection of this kuid has been raised against the phosphate 



LEAVENING AGENTS 169 

and the tartrate powders. Phosphorus in some form is a 
necessary constituent of our diet, although it is doubtful 
if the system can assimilate this element from a phosphate. 
The tartrate powders are considered the most wholesome 
because the acid is obtained from such a commonly used 
fruit as the grape. Being an organic acid, it can be oxy- 
dized so as to furnish energy to the human system. By the 
action of the acid potassium tartrate on sodium bicarbonate 
when the baking powder is used, the compound sodium 
potassium tartrate, or Rochelle salt, as it is commonly 
called, is formed. This salt has a marked physiological 
action on the system, being laxative in its action, so that 
if a considerable amount of bread or cake which has been 
raised by a tartrate baking powder is consumed, its effect 
may be quite serious. The use of large quantities of bread 
or cake raised with baking powder seems to be attended 
with some liability of injury to the health, no matter what 
baking ]3owder is used. The most wholesome bread is 
undoubtedly that raised by means of yeast. 



EXPERIMENTS 

35. Testing baking powders for alum. The presence of alum in 
baking powders may be tested for in the following manner: To a 
few grams of the powder 25 ccm. of water is added. When the 
gas has escaped, a few cubic centimeters of dilute hydrochloric acid 
is added and the starch which is insoluble is filtered off. To a small 
portion of the filtrate a few drops of barium chloride solution are 
added. A heavy white precipitate indicates the presence of sulphates, 
which constitute a portion of the alum. 

To another portion of the hydrochloric acid solution caustic soda 
solution is added drop by drop. A white gelatinous precipitate may 
be calcium phosphate, aluminium phosphate, or aluminium hydroxide. 
Caustic soda is added until the solution is alkaline, and then a con- 



170 PURE FOODS 

siderable excess is added and the solution warmed. If the precipitate 
dissolves entirely, calcium is absent and aluminium is present, which 
may be confirmed by adding hydrochloric acid until the solution is 
acid to litmus paper, and then making it alkaline with ammonia and 
warming. A white flocculent precipitate proves the presence of alu- 
minium. If both sulphates and aluminium are found, alum was pres- 
ent in the baking powder. If the precipitate obtained with caustic 
soda does not give a clear solution with caustic soda, calcium may 
be present. In that case the solution is filtered and tested for alu- 
minium as already directed, as the baking powder may have been 
prepared with both alum and calcium phosphate. 

Aluminium may also be tested for by the following simi:)le 
method : Place 2 gm. of the baking powder in a porcelain or 
platinum dish and heat with the Bunsen burner until the powder 
is burned to a nearly white ash. Extract with boiling water and 
filter. To the hot clear filtrate add ammonium chloride solution 
until a distinct odor of ammonia is given off. A white flocculent 
precipitate is evidence of the presence of aluminium. 

Another simple test is carried out as follows : Logwood extract 
is prepared by covering some logwood chips with water and bringing 
to a boil. This is repeated four times, the last extraction being re- 
served for use. A few grams of the baking powder are treated with 
water. When effervescence ceases, the solution is made strongly 
acid with acetic acid and a few drops of the logwood extract added. 
A bluish-red color indicates the presence of alum. 

36. Testing baking powders for phosphates. In order to make the 
test for calcium phosphate, the precipitate obtained in Experiment 35, 
which does not dissolve in caustic soda, may be used. It is dissolved 
in a few drops of hydrochloric acid, a few cubic centimeters of ammo- 
nium oxalate are added, and the solution made alkaline with am- 
monia. A finely divided white precipitate is evidence of the presence 
of calcium. 

In order to test for phosphoric acid, a fresh portion of the baking 
powder is treated with water and the starch filtered off. Equal vol- 
umes of dilute nitric acid and ammonium molybdate solution are 
added and the mixture thoroughly shaken or stirred. A yellow, finely 
divided precipitate which forms somewhat slowly is evidence of the 
presence of a phosphate. If calcium has also been found, the pres- 
ence of calcium phosphate has been proved. 



LEAVENING AGENTS 171 

37. Testing baking powders for tartaric acid. A baking powder 
may be tested for the presence of tartaric acid as follows : A solution 
of resorcin in sulphuric acid is prepared by dissolving 1 gm. in 
50 gm. of concentrated sulphuric acid. Five gm. of the baking pow- 
der are treated with 250 ccm. of cold water. After allowing the car- 
bon dioxide gas to escape and shaking thoroughly for a few minutes, 
the starch is filtered off and the filtrate evaporated to dryness on 
a water or steam bath so as to avoid charring the tartaric acid. 
A portion of the dry residue is treated with a few cubic centimeters 
of sulphuric acid solution of resorcin and warmed until the white 
fumes of sulphuric acid just begin to appear. If tartaric acid is 
present, the liquid assumes a beautiful wine-red color. The color 
disappears on the addition of water. As concentrated sulphuric acid, 
especially when hot, reacts rather violently with water, the acid 
should be allowed to cool and the water added very slowly. 

Another portion of the dry residue obtained from the water ex- 
tract of the baking powder may be tested as follows : The dry resi- 
due is dissolved in a few cubic centimeters of water, transferred to 
a clean test tube, and a few drops of silver nitrate solution added. 
On shaking for a few minutes a white crystalline precipitate is 
formed if tartaric acid is present. Dilute ammonia is added drop by 
drop until the precipitate is dissolved. The solution is diluted some- 
what and the test tube placed in warm water. If a mirror of metallic 
silver is formed on the test tube, the presence of tartaric acid is in- 
dicated. A brown precipitate of metallic silver is also generally 
formed in the solution. If the test tube is not perfectly clean or the 
water too hot, the mirror may not form and only the brown precipi- 
tate be produced. It is advisable to carry out preliminary experiments 
on pure cream of tartar or tartaric acid, in order to become familiar 
with the method before making the test on a baking powder. 



CHAPTER XVII 

SPICES AND CONDIMENTAL FOODS 

Importance of spices in the diet. Substances which are 
added to foods simply to give an agreeable flavor are called 
condimental foods. In most cases their nutritive value is 
very slight. They are of importance in the diet because 
they serve to stinuilate the appetite and increase the flow 
of the digestive fluids. The digestive organs are to such 
an extent controlled by the nervous system, that in many 
cases little or no digestion takes place if food is introduced 
into the stomach in such a manner that the individual is 
not aware of being fed. This experiment has been re- 
peatedly tried on animals. It has long been known that 
hasty eating, with little or no consciousness of the food 
being eaten, leads to indigestion. While many explanations 
have been given for this observation, probably one of the 
most important ones is the fact that under these circum- 
stances the digestive organs are not properly stimulated. 

Digestion stimulated by attractive foods. It is for a 
similar reason that the preparation of food so as to make it 
attractive in appearance is important. The color and odor 
as w^ell as the taste of food, and pleasing surroundings, all 
tend to arouse the appetite, stimulate the flow of the di- 
gestive fluids and increase their strength. 

Origin of condiments. Almost all substances used as 
condiments are of vegetable origin, the seeds, fruits, buds, 
flowers, bark, or roots being taken, depending upon the part 
of the plant which contains the aromatic principle. In 

172 



spicEkS and condimental foods 173 

many cases the flavor of the pure substance is not agreeable, 
but becomes so when added in proper quantity to otlier 
foods. Frequently a still finer flavor is obtained when 
several condimental substances are blended in foods, because 
a combination of several flavors seems to be most agreeable 
to the palate. Similarly, it has been found that the natural 
flavor of vegetable substances is generally due to the pres- 
ence of several chemical compounds, many of which are 
volatile oils. In many cases these oils can })e separated in 
pure form, such as clove, lemon, mustard, nutmeg oil, etc. 
Being volatile, they give agreeable odors, and if condiments 
are added to hot or boiling foods, much of tlie flavor is lost. 

Allspice. Tins spice is the dried fruit of an evergreen 
tree which grows in the West Indies and is especially cul- 
tivated in Jamaica. The berries are gathered before they 
are fully ripe, as at this stage they give the best aroma. If 
the dried berry is broken open, it is found to consist of two 
cells, each of which contains a single seed. The principal 
constituents of allspice are a volatile oil (which produces 
the characteristic flavor), starch, tannin, mineral matter, 
protein, and crude fiber. 

Cinnamon, or cassia, as it is often called, is the bark of a 
tree which is cultivated in the islands of Ceylon, Sumatra, 
and Java, as well as in some parts of tropical Asia. The 
thin inner bark of the tree is used, and comes into commerce 
in long cylindrical rolls of a brownish-yellow color. A 
cheaper grade, which is generally called cassia, is the bark 
of a tree which grows hi Chma, Indo China, and India. As 
the outer bark is usually left on, this product is thicker and 
heavier than the Ceylon cinnamon. It is also of a darker 
color and coarser texture. Cassia buds are also found on 
the market, both whole and powdered, and are the dried 
flower buds of tl^e China cassia. 



174 PURE FOODS 

The flavor of cinnamon is due to the presence of from 1 to 
2 per cent of a volatile oil which has a very pungent and 
intensely sweet taste. A somewhat bitter taste is due to the 
presence of a small amount of tannin. Other constituents 
are starch (16-30 per cent), crude fiber, ash, protein, 
and water. 

Cloves are the dried undeveloped flowers of the clove 
tree. This is an evergreen tree which is cultivated in Brazil, 
Ceylon, India, the West Indies, and other tropical countries. 
When the green buds begin to turn red, they are gathered 
and dried in the sun. They then acquire a deep brown 
color. On close examination of the clove, the four branch- 
ing sepals can be seen surrounding the overlapping petals 
which mclose the stamens and pistil of the flower. 

Composition of cloves. The strong pungent odor and taste 
is due to the volatile clove oil, of which from 10 to 20 per 
cent is present. The astringent taste is due to tannin, of 
which about 18 per cent is present. Mineral matter, starch, 
crude fiber, and protem constitute the remainder of the 
composition of cloves. 

Cayenne pepper is the dried fruit pods of an herb which is 
cultivated in all temperate and tro23ical regions of the earth. 
A large number of species of the plant are known and 
cultivated, giving pepper varying considerably in color and 
pungency of flavor. The cayenne and chili varieties give 
long and slender pods of great pungency. The Hungarian 
red pepper is known £is ])aprika, and is a very mild variety. 

Composition of cayenne. While cayenne contains a small 
amount of oil, the pungent taste of this pepper is due to 
the presence of an alkaloid known as capsicin. The red 
coloring matter which is present in the pod is an important 
constituent. Fiber, ash, protein, etc., constitute the remain- 
der of the pepper. 



SPICES AND CONDIMEXTAL FOODS 175 

Ginger is the rootstock of an herb which grows to a height 
of from tliree to four feet. It is cultivated very extensively 
in India, China, tropical America, Africa, and Australia. 
Most of the ginger of commerce comes from Calcutta. When 
the plant is a year old and the stem has withered, the root 
is dug up. By different treatment of the root black or 
white ginger is produced. If the root when freshly dug is 
scalded to prevent sprouting and is dried at once, black 
ginger is produced. If, on the other hand, the bark is 
removed to prevent sprouting, white ginger is produced. It 
is sometimes made still whiter by bleaching or sprinkling 
with carbonate of lime. The white ginger is less aromatic 
and is generally considered inferior to the black ginger. 
This is largely due to the fact that the bark contains a large 
amount of pungent resin, which, together with a volatile oil, 
gives the characteristic flavor to the root. About 2 per cent 
of an aromatic oil and from 3 to 4 per cent of a fixed oil 
and resin is present. The remaining constituents are starch 
(about 50 per cent), crude fiber, protein, ash, and water. 

Mustard is the seed of an herb which is cultivated exten- 
sively throughout the United States and Europe. There 
are two varieties, known as white and black mustard, 
although they are often known as yellow and brown mus- 
tard. The seed of black mustard is dark brown on the 
outside and yellow within, while that of white mustard is 
pale yellow. The ground mustard is generally a mixture 
of both species. 

Composition of mustard. Both black and white mustard 
contain valuable ferments known as myrosin and sulpho- 
cyanate of sinapine. Black mustard also contains sinigrin, 
or myronate of potash, which is not found in white mus- 
tard, and which, upon being moistened with water under 
the action of the ferment also present in the seed, forms 



176 PURE FOODS 

the volatile oil of black mustard. White mustard, on the 
other hand, contains a glucoside, sinalbin, not present in 
black mustard, which in the presence of water and the fer- 
ment myrosin also forms by hydrolysis an oil characteristic 
of white mustard. 

Powdering of mustard. In preparing the ground nnis- 
tard the seeds are first crushed and the hulls separated 
from the meats. In order to grind the latter a considerable 
portion of the fixed oil must be removed. This is done by 
subjecting the crushed seeds to hydraulic pressure. The 
press cake is then powdered. 

Nutmeg and mace are obtained from the nutmeg tree, 
which is a native of the Malay Archipelago. The nutmeg 
of commerce is the seed obtained from the fruit of the tree. 
When gathered, the seed is surrounded with a thick cover- 
ing. It is dried in the sun or by artificial heat for about 
two months. The outer covering dries and becomes sepa- 
rated from the kernel and can be easily broken loose. It 
is known in commerce as mace. The nut is washed in milk 
of lime and dried or sprinkled with dry air-slacked lime. 
This treatment is said to prevent sprouting and to ward off 
the attacks of insects. Some nutmegs are sent into com- 
merce without the lime treatment, and are known as l)rown 
nutmegs. Nutmegs differ in shape from nearly splierical to 
an elongated oval shape. 

Composition of nutmegs. Nutmegs contain from 2.5 to 
4 per cent of a volatile oil, 31 to 37 per cent of fat, 30 
to 40 per cent of starch, 7 to 10 per cent of crude fiber, 
about 5|^ per cent of albuminoids, 2 to 3 per cent of ash, and 
4 to 1 2 per cent of water. The composition of mace is very 
similar to that of nutmegs. 

Wild mace. The most common adulterant of mace is the 
so-called false or wild mace, commonly known as Bombay 



SPICES AND CONDIMENT AL FOODS 177 

mace. It is almost entirely devoid of odor and taste, and 
therefore lowers the strength of true mace when mixed 
with it. 

Pepper is the dried berry of the pepper plant, which grows 
in the East Indies and other tropical countries. It is a 
climbing shrub, which grows to a height of from twelve to 
twenty feet. When the fruit begins to turn red, it is 
gathered and dried. It then shrivels up and turns black. 
There are a good many varieties of black pepper which 
have been named from the localities from which they are 
produced or from which they are shipped, such as Singapore, 
Sumatra, Malabar, Penang, Mangalore, etc. 

White pepper. If the pepper berry is allowed to ripen 
and the skin removed, white pepper is produced. In some 
cases white pepper is produced by removing the skin from 
black pepper. White pepper is named in the same manner 
as the black varieties, such as Siam, Singapore, Penang, etc. 
Tlie pungent taste of pepper is produced by an essential 
oil known as pepper oil, of which from 0.5 to 2 per cent is 
present. There is also present from 6 to 10 per cent of a 
nonvolatile oil. The odor and sharp, biting taste of pepper 
is partly due to the presence of two alkaloids, piperidine 
and piperine, of which about 5 per cent is present. From 30 
to 60 per cent of starch, ash, water, and protein constitute 
the remainder of the spice. 

Adulteration of spices. On account of their high price, 
spices have been subjected to a great deal of adulteration. 
This is especially true of powdered spices, to which a great 
variety of inert powdered material can be added without 
much fear of detection by the average consumer. Com- 
monly used material of this kind includes the ground 
shells of most nuts, sucli as English walnuts, Brazil nuts, 
almonds, coconuts, etc. Easily obtauied waste products 



178 PURE FOODS 

of various foods, such as cocoa shells, buckwheat hulls, 
ground olive, and date stones, are frequently used; while 
spruce, oak, and red-sandalwood sawdust has at times 
been found. A microscopic examination will frequently 
show the presence of these foreign substances. A given 
spice will be mixed with the adulterant, which most nearly 
resembles it in color and general appearance. In many cases 
the color is imitated by means of a dye. Turmeric, for 
instance, can be used to produce a color similar to that of 
mustard. Starch and various cereal flours have also been 
considerably used. The ground bark of various trees, more 
especially the elm, has been used to adulterate ground cin- 
namon. Ground pepper shells, stems, and sweepings are 
frequently added to ground pepper. Such material is 
known in the trade by the symbol '' P.D. " (pepper dust), 
and this symbol has been adopted to designate any material 
suitable for the adulteration of pepper or other spices. 

Grinding nutmegs. Ground nutmegs are subjected to 
a rather peculiar adulteration. As it is difficult to grmd 
whole, sound nutmegs on account of the rather large 
amount of oil present, a special grade, known as ''grind- 
ing nutmegs," has been used to some extent. These are 
moldy, worm-eaten, fragmentary nutmegs, which are im- 
ported for the purpose of grmding. When detected, the 
importation or sale of such spices is prevented. 

Exhausted spices. Although powdered spices are far 
more commonly adulterated than the wdiole spice, some adul- 
teration of the latter has been practiced. Where the oil or 
other flavoring matter of a spice can be extracted and sold, 
the completely or partially exhausted spice is sometimes 
sold. Aside from a slightly wrinkled or shriveled condi- 
tion, the general appearance of such spices is the same as 
that of spices which have the full flavoring strength. The 



SPICES AND C0:N^DIMENTAL foods 179 

detection of this adulteration is more difficult when such 
exhausted spices are mixed with those of full strength. 
The exhausted spice is also ground and mixed with the 
ground, pure spice, very materially reducing the strength 
of the latter. As there is a good market for clove oil, this 
spice has been largely subjected to this form of adultera- 
tion. The same is true of ginger, because the extract of 
this spice is largely used. 

Microscopic examination of spices. A great many of the 
forms of adulteration of spices may be detected by exami- 
nation under the microscope. For this purpose a magnifi- 
cation of about 125 diameters is sufficient. Samples of 
pure whole spices are ground and compared with the 
ground spice as purchased.^ 

iFor further information on this subject, the reader is referred to 
Winton's "Microscopy of Vegetable Foods" and Leach's "Food Inspec- 
tion and Analysis." 



CHAPTER XVII r 

FLAVORING EXTRACTS 

Utility of flavoring extracts. A number of vegetable 
substances contain flavoring matter which can be extracted. 
This is advantageous because such extracts are more con- 
venient for use, and undesirable portions of tlie vegetable 
substances need not be introduced into the food. In some 
cases both the extract and the whole vegetable product is 
in use. By means of these highly flavored substances 
many wholesome and nutritious foods which are quite lack- 
ing in flavor are made very palatable. Vanilla and lemon 
are by far the most commonly used flavoring extracts. 

The vanilla bean. Vanilla extract is made from the 
vanilla bean. This bean is the fruit of the orchid Vanilla 
plamf(-Ua. It is a climbing parasite, which fastens itself to 
the bark of trees in moist tropical climates. It is indige- 
nous to Central America and the West Indies, but the finest 
beans are produced in Mexico. It is frequently cultivated 
together with the cacao tree, as both the vanilla vine and 
the cacao tree require a rich soil, shade from large trees, 
and a warm climate. While the vine clings to the tree, it 
obtains its nourishment from the air through its tendrils 
and aerial rootlets. It blossoms in October and November, 
and the pods are gathered in May, June, and July. The 
pods are green at first, and when they turn brown are ready 
to be gathered. The drying of the pods is the most impor- 
tant part of their preparation for market, as it is during 
this process that the flavor is developed. When picked, 

180 



FLAVORING EXTRACTS 



181 



the beans are without odor, but this develops during a proc- 
ess of fermentation or sweating. The drying in the sun 
requires about a month, and is said to give the best product. 




Fig. 30. The Vanilla Vine, showing Leaves, Flowers, and the 
Vanilla Beans, as well as the Tree to which the Vine clings 

Recently an artificial method of drying by means of air 
dried over calcium chloride has come into use. This process 
gives a much moTe uniform product. 



182 PURE FOODS 

Preparation of vanilla extract. When the curing and 
drying process is completed, the beans are tied in bundles 
and sent to market, where the best quality commands very 
high prices, sometimes reaching fifteen dollars per pound, 
although four to six dollars is a more common price. The 
extract is prepared by treating the beans with strong 
alcohol and sugar. For this purpose they are cut up into 
rather small pieces and soaked in the alcohol for some 
time. The alcoholic extract is drained off and bottled for 
the market. To a limited extent the beans are sold for use 
in foods, small portions being cut off and put into the food 
to be flavored. 

Varieties of vanilla bean. A considerable number of dif- 
ferent varieties and grades of beans are found on the market. 
The Mexican vanilla beans are considered the best, being 
from 8 to 10 inches long and from J to 1 inch thick. They 
are dark brown in color and feel waxy to the touch. The 
Bourbon beans, which are shorter than the Mexican, are 
considered next in grade. They are grown in the Isle of 
Reunion. Still shorter and cheaper beans are grown in 
Mauritius and South America. The shorter beans are 
the Tahiti or wild vanilla beans. 

Vanillin. The pecuHar flavor of the vanilla bean is very 
largely due to the presence of a white crystalline substance 
which is known as vanillin. Crystals of this compound 
may frequently be seen on the outside of the vanilla beans. 
This substance has been artificially prepared by chemists 
and is manufactured in large quantities. A number of 
other substances are also present, which modify and im- 
prove the flavor. These substances are known collectively 
as resin, 4 to 11 per cent being present in vanilla beans. 
There are also present considerable quantities of wax, sugar, 
tannin, and gum. Although the flavor of the beans is 



FLAVORING EXTRACTS 183 

largely due to the presence of vanillin, the most highly 
prized varieties do not contain the largest percentage of 
vanillin, as is shown by the following table : ^ 

TABLE XXLX 

Vanillin in A^anilla Beans 

Per cent 

Mexican beans 1.69 

Bourbon beans 2.48 

Java beans 2.75 

Pure vanilla extract contains from 0.1 to 0.2 per cent of 
vanillin, about 20 per cent of sugar, 40 per cent of alcohol, 
and 2 to 4 per cent of other extractive matter, includ- 
ing the vanilla resins. Some extracts are prepared with 
glycerin instead of sugar. 

The tonka bean. This bean has been very largely used 
in place of the more expensive vanilla bean in making 
extracts. It is the seed of a large tree which is native 
to Guiana. The tonka bean is almond-shaped, and dark 
brown or black. The flavoring matter in this bean is an 
entirely different substance from that present in the vanilla 
bean. It is known as coumarin and has a much sharper 
and less pleasant odor than vanilla. It is a white crystalline 
powder in the pure state. The flavoring matter is ex- 
tracted from the tonka bean in exactly the same manner as 
from the vanilla bean. The extract is generally of a darker 
color than true vanilla extract. It also contains resinous 
matter somewhat similar to that of the vanilla bean. 

Tonka extract. While tonka extract is often sold as va- 
nilla extract, a much more common practice consists in sub- 
stituting tonka beans for a portion of the more expensive 
vanilla extract. Both such mixed extracts and the pure 

1 Leach, Pood Inspection and Analysis, 1909, p. 857. 



184 PURE FOODS 

tonka extract find a ready sale, because conmarin, the flavor- 
ing matter of the tonka bean, has a much sharper odor, 
giving the extract greater flavoring power, unless delicacy 
of flavor is desired. The sale of the tonka extract or mixed 
tonka and vanilla extract is not illegal unless those prepara- 
tions are sold as pure vanilla extract. They must be labeled 
"Tonka Extract " or " Tonka and Vanilla Extract," so that 
the purchaser clearly understands what he is buying. 

Artificial extracts. As both vanillin and coumarin are 
manufactured on a large scale and can be sold a great deal 
cheaper than the natural flavoring matter, a great deal of 
so-called flavoring extract has been made and sold which 
contains no extract at all of vanilla or tonka beans. Such 
artificial or compound extracts are prepared by dissolving 
vanillin or coumarin crystals and sugar in alcohol and 
water and adding some appropriate coloring matter. Cara- 
mel or burned sugar has been very largely used as coloring 
matter. Recently prune juice, which is an alcoholic extract 
of prunes, has been sold under various trade names and 
used to some extent as coloring matter. In many cases a 
small quantity of vanilla or tonka extract is added to give 
color and flavor. 

The table on page 185 gives the composition of a number 
of vanilla extracts as purchased on the market. 

A true vanilla extract should contain about 38 per cent 
of alcohol and between 0.1 and 0.2 per cent of vanillm. 
Coumarin should be absent. 

Lemon extract is a solution of the flavoring matter of 
lemon peel in alcohol. It is prepared by subjecting lemon 
peel to the action of strong alcohol. The flavoring matter 
in the lemon peel is a volatile, fragrant oil, which is solu- 
ble in alcohol. When pure, the oil is almost colorless, but 
sufficient coloring matter is dissolved by the alcohol to 



FLAVORING EXTRACTS 



185 



TABLE XXX 
Composition of Vanilla Extracts as Purchased 



A^olunic > 


Solids 


Ash 


Alcohol 


Vanillin 


Coumarin 


Ccm. 


Per cent 


Per cent 


Percent 


Per cent 


Per cent 


47 


6.55 


0.18 


16.1 


0.095 






12.01 


0.39 


37.7 


0.10 






21.15 


0.34 


28.9 


0.059 






13.52 




13.0 


0.23 


0.88 




12.49 


0.14 


25.37 


0.21 




54 


9.71 


0.09 


15.00 


0.06 




47.5 


7.73 


0.2 


20.00 


0.28 






11.40 


0.05 


18.00 


6.02 


0.03 




14.13 


0.32 


28.30 


0.15 




46 


8.51 


0.29 


23.16 


0.05 




53 


10.72 




10.44 


0.05 


0.07 




4.13 


0.05 


9.85 


0.15 


0.093 




13.25 


0.12 


14.93 


0.15 


0.07 


26.5 


10.70 


0.32 


28.60 


0.10 




56.5 


9.65 


0.45 


45.36 


0.155 




57.5 


14.12 


0.17 


22.35 


1.12 


0.02 


60 


13.10 


0.20 


18.42 


0.27 




57 


14.05 


0.36 


17.01 


0.15 






10.53 


0.02 


9.84 


0.842 


0.07 




10.55 


0.29 


36.7 


0.168 




17 


44.0 


0.50 


18.77 


5.96 


1.82 



give the extract a light yellow color. The pure lemon oil 
is prepared in large quantities from the fresh lemon peel 
by pressing the peel against a rough sponge which is kept 
moist with water. As the oil floats on the water, it is 
easily separated and purified. A great deal of lemon extract 
is prepared by dissolving this oil in alcohol and coloring 
the solution with a strong alcoholic extract of lemon peel. 
In some cases coal-tar dyes or other yellow coloring matter 

1 Two ounces is equal to 57 com. The ordinary bottle of vanilla extract is 
understood to be a two-ounce bottle. 



186 PURE FOODS 

is added. The United States standard for lemon extract 
is 5 per cent of lemon oil by volume. There are many 
brands of lemon extract on the market containing more 
than this amount of oil. 

Adulteration of lemon extract. This consists almost in- 
variably in the reduction of the amount of lemon oil present. 
This results from the fact that the most expensive con- 
stituent of the extract is the alcohol. In order to hold 5 
per cent of lemon oil in solution, at least 80 per cent of 
alcohol must be present. In attempting to reduce the 
amount of alcohol in the extract, the amount of lemon oil 
held in solution becomes less and less, until with 45 per 
cent of alcohol practically no oil at all can be present. 
Such an extract will, however, give a very distinct odor 
of lemon, and if colored yellow will find a ready sale. The 
absence of lemon oil can easily be shown by adding twice 
the volume of water. If the mixture remains clear, no oil 
can be present. Extracts of standard strength give a white 
milky liquid, due to the particles of oil held in suspension. 
The amount of oil present is proportional to the degree of 
cloudiness produced. Methyl alcohol has also been used 
instead of ethyl alcohol in making lemon extract. 

Orange extract is prepared from orange peel by a method 
similar to that used m the preparation of lemon extract. 
It is an alcoholic solution of orange oil. It should contain 
at least 5 per cent of orange oil. 

Almond extract is an alcoholic solution of the oil of 
bitter almonds, and should contain at least 1 per cent of 
this oil. The oil must first be extracted from the almonds 
and purified in order to free it from the poisonous hydro- 
cyanic acid. 

Other flavoring extracts. Extracts of a number of other 
aromatic vegetables are on the market, as well as extracts 



FLAVORING EXTRACTS 187 

of very nearly all the common spices. Generally these 
extracts are alcoholic solutions of the oils which give the 
characteristic flavor to the spices. 

Fruit flavors. Attempts to extract the natural flavoring 
matter in fruits have in most cases been unsuccessful. 
Practically all of the fruit essences on the market are arti- 
ficial mixtures of chemical compounds, which imitate more 
or less closely the natural fruit flavors. Several chemical 
compounds have been prepared, which have an odor remark- 
ably similar to that of some fruits. Such substances are 
amyl acetate, having an odor like bananas ; butyric ether, 
resembling the odor of pineapples ; and amyl valerianate, 
sometimes called apple oil. These substances are com- 
pounds of various organic acids, and alcohol. In other cases 
where no single substance has been found the odor of 
which closely resembles that of the fruit to be imitated, a 
mixture of several chemical substances is made to imitate 
the natural flavor. If no poisonous substances are present, 
and if not sold as pure fruit flavors, the sale of such 
artificial fruit flavors is not illegal. 



APPENDIX 

CHEMICALS AND REAGENTS 

The amount of eacli chemical given is in all cases sufficient 
for the performance of all the experiments given in the test 
for which it is required. In a good many cases it is much more 
than necessary and would be sufficient for a large class. It is 
often not economical to purchase chemicals in very small quan- 
tities. All chemicals in this list, as well as the apparatus given 
in the following list, may be purchased of Eimer & Amend, 
Third Avenue and 18th Street, New York. 

Acetic acid (i lb.). The strongest commercial quality of this 
acid is known as glacial acetic acid and is very nearly 100 per cent 
pure. Dilute acetic acid is prepared by adding 40 ccm. of the gla- 
cial acid to 100 ccm. of water. This strength is commonly used. 

Agar-agar. This is a dried seaweed which has the property of 
absorbing a large amount of water and solidifying into a jelly. 

Ammonia (1 lb.). The concentrated c.p. solution as purchased 
must be diluted with 2 volumes of water for ordinary use. It 
should be kept in a glass-stoppered bottle. If acid of any kind is 
accidentally spilled on clothing, ammonia should be applied. 

Ammonium molybdate (1 oz.). A white crystalline salt used 
in nitric acid solution as a test for phosphoric acid, which pro- 
duces a yellow, finely divided precipitate. The solution is pre- 
pared as follows: 7i gm. of ammonium molybdate are dissolved 
in 50 ccm. of water with the addition of a little ammonia if 
necessary. This solution is poured with constant stirring into 
a mixture of 25 ccm. of concentrated nitric acid and 25 ccm. of 
water. The solution is placed in a glass-stoppered bottle and 
allowed to stand for several days. The clear liquid is added to 
the solution to be tested for phosphoric acid. 

189 



190 PURE FOODS 

Amyl alcohol (^ lb.). A colorless liquid. 

Barium chloride (1 oz.). White crystals. A solution is pre- 
pared by dissolving 1 oz. in 200 ccm. of water. 

Borax (1 oz.). A white powder. 

Bromine (1 oz.), A dark red, fuming, highly corrosive liquid. 
Great care should be taken not to allow liquid bromine to come 
in contact with the skin nor to breathe the fumes. A few drops 
are placed in a glass-stoppered bottle, which is filled with dis- 
tilled water and well shaken. This saturated solution is called 
bromine water. 

Carbon disulphide (^ lb.). A heavy volatile liquid. 

Caustic soda (i lb.). A white solid usually sold in sticks. 
Both the solid caustic and the solution should be kept well 
stoppered, as the carbon dioxide of the air converts it into 
sodium carbonate. The caustic soda solution is prepared by 
dissolving 20 gm. in 100 ccm. of water. 

Ether (^ lb.). A very volatile, highly inflammable liquid. The 
vapor forms an explosive mixture with the air. It should be 
kept in a bottle stoppered with a well-fitting cork, preferably 
in a cool place. It should never be handled near a flame of 
any kind. 

Fehling's solution. This is an alkaline solution of copper, 
which is used to test for reducing sugars, such as dextrose, 
levulose, etc. When the solution is boiled with such sugars, 
the copper is reduced to the cuprous condition, which is indi- 
cated by the change from a blue transparent solution to a 
bright red precipitate. The solution is prepared immediately 
before it is used by mixing equal portions of two solutions 
A and B, which are prepared as follows : 

A. Dissolve 7 gm. (about i oz.) of crystallized sulphate of 
copper in 100 ccm. of water. 

B. Dissolve 34.6 gm. of crystallized Eochelle salt in 45 ccm. 
of water, also 25 gm. of caustic soda in 40 ccm. of water. Mix 
these two solutions and dilute to 100 ccm. 

Ferric chloride (1 oz.). A red solid easily soluble in water. The 
solution is prepared by dissolving 5^ gm. in 100 ccm. of water. 



APPENDIX 191 

Ferrous sulphate (1 oz.). A green crystalline salt. As it is 
not stable in solution, a few crystals are dissolved in water 
when needed. 

Gelatin (gold label). 

Hydrochloric acid (also known commercially as muriatic acid) 
(1 lb.). The acid as purchased is a solution in water of the 
pure acid, which is a gas. The strongest acid sold contains 
about 40 per cent of acid. This solution is a fuming corrosive 
liquid. If spilled on the hands, it is washed off with water. 
If spilled on the clothing, it should be neutralized with am- 
monia and then washed out with water. 

A dilute solution for ordinary use is prepared by mixing 
5 volumes of the strong acid with 8 volumes of water. 

Iodine (1 oz.). A gray-black crystalline solid, which slowly 
volatilizes at ordinary temperatures. It acts on the skin and 
most organic matter. It is readily absorbed by ammonia. It 
is soluble in alcohol and a water solution of potassium iodide. 
The potassium iodide solution gives a blue color with starch. 
It is prepared as follows : 2 gm. of iodine are agitated with a 
solution of 6 gm. of potassium iodide in a few cubic centi- 
meters of water. When the iodine is entirely dissolved, the 
solution is diluted with water until its volume is 100 ccm. It 
should be kept in a glass-stoppered bottle. 

Lead acetate (1 oz.). A white crystalline solid. By heating a 
water solution with lead oxide basic lead acetate is produced, 
which is used to precipitate fruit juices and other soluble 
organic matter. The solution is prepared as follows : 18 gm. 
of lead acetate are dissolved in 70 ccm. of liot distilled water 
and 11 gm. of lead oxide added. The mixture is boiled for 
half an hour with occasional stirring, after which it is allowed 
to settle for a few minutes and the clear solution poured off or 
filtered. Enough distilled water is added to make the volume 
about 81 ccm. The solution must be kept in well-stoppered 
bottles. A dilute solution made by adding about 4 volumes 
of water to 1 volume of the strong solution is suitable for 
ordinary use. 



192 PURE FOODS 

Lead oxide (1 oz.). A heavy yellow to orange powder. 

Limewater. A saturated water solution of calcium oxide. 
It is prepared by treating a few ounces of ordinary lime with 
water, shaking thoroughly, and allowing to stand until the in- 
soluble matter has settled. The clear liquid is siphoned off or 
decanted into a bottle, which should be kept well stoppered. 

Litmus paper. A sheet each of blue and red should be pur- 
chased and cut into strips of convenient size. The paper is 
used to test for acids and alkalies. Acids turn the blue paper 
red, while alkalies or bases turn the red paper blue. 

Magnesium (^ oz.). A white metal which is sold in the form 
of narrow ribbons. 

Methyl alcohol (1 pt.). Also known as wood alcohol. A vola- 
tile combustible liquid. 

Methyl orange (1 oz.). A yellow powder soluble in water and 
used as an indicator for acids and bases. Acids give a red color 
to the solution, while alkalies give a yellow color. The solution 
is prepared by dissolving 1 gm. in 1000 ccm. of distilled water. 

Nitric acid (1 oz.). The pure acid is a fuming, corrosive liquid, 
generally colored reddish on account of the presence of nitrous 
acid. It acts ra^^idly on wood, cloth, the skin, and most organic 
matter. The ordinary concentrated acid contains about one 
third its weight of water. For many purposes a dilute acid 
is prepared by adding 2 volumes of water to 1 volume of the 
concentrated acid. 

Phenolphthalein (1 oz.). A white crystalline solid used in 
alcoholic solution as an indicator for acids and bases. In acid 
solution the indicator is colorless, while alkalies give a deep 
red color. The solution is prepared by dissolving ^^^ gm. in 
100 ccm. of alcohol. 

Phosphoric acid (1 lb.). In its most concentrated form (glacial 
phosphoric acid) this acid is a thick sirupy liquid. For ordi- 
nary use a dilute solution, prepared by adding 3 volumes of 
water, is sufficiently concentrated. 

Resorcin (1 oz.). This organic compound is used in testing for 
tartaric acid. One gram is dissolved in 50 gm. of concentrated 



APPENDIX 193 

sulphuric acid. When heated with even a very small quantity 
of tartaric acid this solution gives a beautiful wine color. 

Rochelle salt (2 oz.). This is the sodium and potassium salt 
of tartaric acid. It has the property of holding copper in 
solution in the presence of an alkali, and is therefore used in 
Fehling's solution. 

Silver nitrate (1 oz.). A white crystalline salt, very soluble 
in water. A solution of convenient strength may be prepared 
by dissolving 3| gm. of the salt in 100 ccm. of water. The 
solution should be kept in a glass-stoppered bottle made of 
dark-brown glass ; or, if this is not at hand, the solution should 
be protected from the light by pasting dark paper around the 
bottle. 

Sodium (metallic) (1 oz.). In the pure state this element is a 
soft silvery-white metal. It oxidizes very rapidly in the air 
and reacts violently with water. It is therefore sold in sealed 
tin cans, and must be kept under kerosene or other mineral oil. 
The oil can be removed from the sodium by means of dry filter 
paper. The metal can easily be cut with a clean dry knife. It 
should not be left exposed to the air or moisture for any length 
of time. 

Sodium carbonate (dry) (1 lb.). A white powder, very solul)le 
in water, composed of sodium and carbonic acid. Its solution 
is strongly alkaline and neutralizes acids. 

Sodium acid sulphite (^ lb.). A white salt, very solul)le in 
water, composed of sodium and sulphurous acid. It is largely 
used as a preservative. 

Starch iodate paper. Starch })aste is prepared as directed on 
page 15. A small quantity of potassium iodate is dissolved in 
water and added to the starch paste. Strips of filter paper are 
dipped into the mixture and hung up to dr}^ Sulphur dioxide 
(fumes of burning sulphur) or sulphurous acid turns the paper 
dark blue and then bleaches it. 

Sulphur (1 oz.). A yellow solid found on the market in rolls 
or as a powder (flowers of sulphur). EoU sulphur is the form 
most soluble in cS-rbon disulphide. 



194 PURE FOODS 

Sulphuric acid (1 lb.). In the pure state this acid is a thick, 
heavy, viscous liquid. It chars paper, wood, and most organic 
matter and reacts violently with water. If spilled on the cloth- 
ing, ammonia should be applied ; if on the skin, it should be 
immediately washed off with cold water. For ordinary use 
dilute acid should be prepared by diluting 1 volume of the 
concentrated acid with 6 volumes of distilled water. The water 
must not be poured into the acid, because the large amount of 
heat developed is liable to produce violent boiling and spatter- 
ing of the acid. When it is poured slowly and with constant 
stirring into the water, no violent action takes place. Both the 
concentrated and dilute acid should be kept in glass-stoppered 
bottles. 

Turmeric paper. This paper may be purchased or it may be 
prepared by dipping strips of filter jmper into an alcoholic 
solution of turmeric and allowing them to dry. Alkalies turn the 
paper red. It is most largely used to detect boric acid. When 
dipped into a solution of this acid to which hydrochloric acid 
has been added, and then dried, a bright red color is produced, 
which is turned green by alkalies. The paper must not be dried 
at a temperature above 100° C. or that of boiling water. 

Witte's peptone (^ lb.). A w^hite powder used in the prepara- 
tion of nutrient gelatin. 

Wood alcohol (1 lb.). Also called methyl alcohol. A colorless, 
volatile liquid obtained by dry distillation of wood. 

APPARATUS 

The following list includes all the apparatus necessary to 
prepare most of the experiments given in the text. The more 
expensive apparatus which would be required in order to per- 
form a few of the most difficult experiments is given in a 
separate list. 

Air oven. This piece of apparatus consists of a copper oven 
which can be heated with a Bunsen burner. A suitable open- 
ing in the top is provided for the insertion of a thermometer, 
so that the temperature can be regulated to suit the substance 



APPENDIX 195 

to be heated or dried in the oven. For many purposes an 
ordinary gas oven is entirely satisfactory. 

Beakers. Thin glass vessels in which liquids may be boiled. 
They may be obtained in a great variety of sizes. For ordinary 
use, nests of beakers having capacities of 2, 4, 6, 8, 10, and 12 oz. 
are satisfactory. 

Bottles. One and one-half dozen glass-stoppered bottles of 
250 ccm. capacity. 

Bunsen burner. In the absence of a suitable stove, Bunsen 
burners are convenient. They are attached to gas jets by 
means of rubber tubing. 

Filter paper. C'ircular paper may be obtained in packages 
of 100 sheets of various sizes. Paper of 121^ or 15 cm. in 
diameter is convenient. 

Flasks. The so-called Florence flasks are flat-V^ottomed and 
suitable for most purposes. A convenient size is 8 oz. 

Funnels are used for holding the paper when filtering. Size 
3 to 4 in. 

Graduates are tall vessels on which the capacity in cubic 
centimeters is marked, and are used for measuring liquids. 
Size 100 ccm. 

Pipestem triangles are wire triangles covered with clay tubing, 
and are used for holding vessels while being heated with the 
Bunsen burner. Size 3 to 4 in. 

Platinum wire (1 ft.). This metal resists the action of most 
chemical reagents and cannot be melted or oxydized in the gas 
flame. The wire is used for inserting drops of solutions to be 
tested in the flame of the Bunsen burner. Size Xo. 25. 

Porcelain dish. These dishes are suitable for evaporating 
liquids, and may be subjected to the full heat of the gas flame. 
Size 3 in. 

Porcelain mortar. Suitable for grinding or mixing chemicals. 
Size 3 in. 

Test tube (^ gross). Suitable for a great variety of tests on 
small quantities of liquid. They may be heated in the Bunsen- 
burner flame. Sife 6 in. 



196 PUEE FOODS 

Thermometers. Chemical thermometers have the scale etched 
on the glass tube and are made entirely of glass. 360° C. 

Tripod (2). An iron stand suitable for the support of beakers 
or other vessels which must be heated with the Bunsen burner. 
A wire gauze should be placed on the tripod in order to dis- 
tribute the heat of the Bunsen burner and to serve as a support 
for the beaker. 

Water bath. A copper or iron vessel suitable for boiling 
water, and fitted with a lid composed of rings so that vessels 
of various sizes may be heated by the steam. As the tempera- 
ture of the steam is 100° C, the vessel heated or its contents 
cannot rise above this temperature. 

Wire gauze (^ doz.). Four-inch squares of iron or copper are 
suitable for most purposes. Wire gauze transmits the heat of 
a gas flame, spreading it over a large surface and protecting 
the vessel heated from direct contact with the flame. 

SPECIAL APPARATUS REQUTREB FOP SOME OF THE 
MORE DIFFICULT EXPERIMENTS 

Balance. The ordinary analytical chemical l)alance is a very 
delicate instrument, and, with a set of weights, can be purchased 
for from $50 to $150. Fairly satisfac^tory results could be 
obtained with a cheaper instrument, which would be some- 
what less sensitive. 

Burette (2). An instrument consisting of a glass tube grad- 
uated to tenths of cubic centimeters and having a stopcock 
attached, so that any desired quantity of liquid may be de- 
livered. The usual capacity is 50 ccm. 

Casserole. A cup-shaped porcelain vessel provided with a 
handle and suitable for heating liquids, especially when it is 
desirable to keep the liquid agitated. A very convenient size 
is 250 ccm. 

Petri dish (1 doz.). These are flat, circular glass dishes pro- 
vided with glass covers. They are used for making bacterial 
cultures and counts. 



APPENDIX 197 

Pipettes. Glass tubes having a bulb at the center and marked 
to deliver a definite quantity of liquid, such as 1 ccm., 5 ccm., 
10 ccm., 25 ccm., etc. For bacteriological work 1-ccm. pipettes 
are used, two dozen being a suitable quantity. Half a dozen pi- 
pettes graduated so as to deliver either 9 or 10 ccm. would also 
be required. These pipettes must be sterilized and kept in a 
sterilized receptacle until used. For this purpose tin or copper 
cans of suitable size, provided with a lid or long test tubes, 
must be employed. The latter may be closed with a plug of 
cotton. 

Platinum. This metal is eminently suited for chemical work 
because it is unaffected by most chemical reagents, and can be 
heated to the highest temperature obtained with the gas flame 
without injury. In making food tests platinum dishes about 3 
in. in diameter are very useful for burning the organic matter of 
foods. Tests on smaller quantities can be carried out on plati- 
num foil, which can also be used for the deposition of copper, 
for which purpose platinum dishes are also well adapted. 



INDEX 



Acetic acid, 189 

Acid, stearic, preparation of, 69 
Acidity, of oils, determination of, 
68 

testing fruit juices for, 152 

titration of, 56 
Acids, fatty, 63 

found in fats and oils. 62, 63 

found in fruits, 143 
Adulterated foods, 18, 22 
Adulterated jams, 151 
Adulteration, of bread, 163 

of cake, 163 

of chocolate, 116 

of cocoa, 112 

of lemon extract, 186 

of spices, 177 

of vegetables, 155 
Agar-agar, 189 

nutrient, preparation of, 59 
Air oven, 194 
Alcohol, use of, as a preservative, 

132 
Allspice, 173 
Almond extract, 186 
Alum, 163 

baking powder, 167 

baking powders, objections to 
use of, 168 

testing baking powders for, 169 
Aluminium, testing baking powders 

for, 170 
Ammonia, 189 
Ammonium molybdate, 189 



Amyl acetate, 144, 187 

Amyl alcohol, 190 

Amyl valerianate, 144, 187 

Aniline dye, experiments with a 

poisonous, 125 
Aniline dyes, 123 

and other food colors, 122 

arsenic in, 124 

methods of proving harmless, 
124, 125 

permitted by United States De- 
partment of Agriculture, 126 

poisonous, 20, 123 

testing for, 154, 158 
Apparatus, 194 
Appendix, 189 
Apples, composition of, 142 
Argols, 143 

Arsenic in food colors, 124 
Artificial extracts, 184 
Artificial jellies, 150 

wholesomeness of, 151 
Ash in foods, definition of, 5 

test for, 16 
Atwater-Mahler bomb calorim- 
eter, 9 

Bacteria, action of, on milk, 45 
action of preservatives toward, 

137 
count of, 57 

danger of consuming large num- 
bers of, 137 
determination of number of, 54 



199 



200 



PUIIE FOODS 



Bacteria, food of, 44 

in milk, 43, 45 

in milk sold in New York City, 58 

plate cultures of, 58 
Bacteria content of milk, varia- 
tions in, 53 
Baking powder, alum, 1(17 

cream of tartar, 1(57 

phosphate, 1G7 
Baking powders, testing for alum, 
109 

testing for phosphates, 170 

testing for tartaric acid, 171 
Balance, 196 
Balanced diet, 23 
Banana oil, 144 
Barium chloride, 190 
Barley flour, 162 
Barn, old-style, 45 
Beakers, 195 
Beets, manufacture of sugar from, 

98 
Benzoate of soda, 139 

harmless, 136 
Benzoic acid, 83 
Bleached flour, 161 
Bomb calorimeter, 9 
Bombay mace, 176 
Borax, 136 

test for, in milk, 40 

testing for, in meat, 85 
Boric acid, 83, 136 
Bread, 159 

adulteration of, 163 

butter, and milk, daily ration of, 
36 

Liebig's method of raising, 166 

raised by carbon dioxide gas, 166 

raising of, 162 

sour, 166 

water in, 163 



Breakfast cocoas, 110 

composition of, 112 
Breakfast foods, 164 
Bromine, 190 
Buckwheat flour, 162 
Buddeized milk, 52 
Bunsen burner, 195 
Bur mills, 91 
Burette, 196 
Butter, 71 

composition of, 71 

constituents of, 72 

flavor of, 73 

foam test for, 76 

milk test for, 76 

process, 73 

production of, 71 

renovated, 73 
Butter fat, 72 

composition of, 72 
Butterine, 74 
Buttermilk, 39 
Butyric ether, 187 

Caffeine, 112 

Cake, adulteration of, 163 
Calculation of calorific value, 10 
Calorie, a measure of the energy 
of food, 7 
definition of, 8 
Calorific value, calculation of, 10 
Calorimeter, description of, 8 
Candies, 101 

Candy, amount of dyes in, 126 
and nuts, adult ration of, 102 
detection of glucose in, 121 
flavoring matter for, 121 
food value of, 101 
not a sustaining food, 103 
sugars present in, 103 
use of coloring matter in, 118 



INDEX 



201 



Candy, use of eggs in, 118 

use of gelatin in, 118 

use of sulphurous acid in, 104 
Cane sugar, 3 

manufacture of, 98 

refining of, 08 
f!anned fruits, 148 
Canned vegetables, 155 

testing for copper sulphate, 157 

testing for sulphur dioxide, 1 57 
Carbohydrates, 88 

calorific value of, 10 

definition of, 2 

importance of, in the diet, 88 

solubility of, 3 
Carbon dioxide gas, used for rais- 
ing bread, 100 
Casein, 34, 40 
Casserole, 190 
Cassia, 173 
Catsup, 139, 157 
Caustic soda, 190 

normal solution of, 50 
Cayenne, composition of, 174 
Cayenne pepper, 174 
Cellulose, 2, 3 
Centrifuge, 99 
Cereals, 159 
Certified milk, 48 
Charcoal filters, 93, 94 
Chemical composition of fats, 01 
Chemical preservatives, classed as 
drugs, 135 

digestion experiments on, 130 

efficiency of, 133 

for meats, 83 

tasteless, 133 
Chemicals, 189 
Chicago stockyards, 79 
Children, influence of the milk 
supply on the death rate of, 53 



('hildren, rations for, 25 
Chlorophyll, 141 
Chocolate, 101, 114 

adulteration of, 110 

composition of, 114 

cooling room for, 120 

production of, by grinding cocoa 
beans, 115 
Chocolate creams, 102, 110 

food value of, 101, 10(5 
Cinnamon, 173 

flavor of, 174 
Citric acid, 144 

Cleanliness vs. preservatives, 138 
Cloves, 174 

composition of, 174 
Cocoa, 101 

adulteration of, 112 

breakfast, 110 

composition of breakfast, 112 

fruit of, gathering, 107 

history of, 100 

hulls of, 108 

manufacture of, 113 

Mexican, origin of, 100 

nutritive value of, 112 

stimulating properties of, 112 
Cocoa beans, drying in the sun, 
109 

grinding into chocolate, 115 

roasting of, 107 

roasting and hulling. 111 
Cocoa butter, 108 
Cocoa nibs, 108 
Cocoa tree, 100 
Coconut oil, 04 
Coefficient of digestibility, 20 
Cold storage, 130 

length of, 131 

of fruits, 147 

of meat, 82 



202 



PUEE FOODS 



Coloring matter in candy, 118 
Common salt as a preservative, 132 
Comparative cost, of foods, 29 

of milk, cream, and butter, 38 
Composition, of foods, 1, 11 

of milk, 35 
Concentration of sirup, 96 
Condimental foods, 172 
Condiments, origin of, 172 
Constituents of milk, 34 
Conversion of starch into sirup 

and sugar, 92 
Converters, 92 
Cooling room, 120 
Copper, as coloring matter in vege- 
tables, 156 
Copper sulphate in vegetables, test- 
ing for, 157 
Corn, amount used in producing 
corn products, 98 

manufacture of starch from, 90 

storage of, 89 

structure of a grain of, 90 
Corn oil, production of, 91 
Corn sirup, amount consumed in 
the United States, 98 

composition of, 96 
Cost, of a daily ration of a single 
food, 29 

of a day's food of various arti- 
cles, 30-32 

of food, 23 

of milk, cream, and butter, 38 
Cottolene, 66 
Cottonseed oil, 64 

consumption of, 65 

test for, 70 
Count of bacteria, 57 
Cream, 38 

comparative cost of, 38 
Cream of tartar, 143 



Cream of tartar baking powders, 

167 
Cream-casting room, 119 

Daily ration, 23 

of bread, butter, and milk, 36 
of milk, 36 
Day's food of various articles, cost 

of, 30-32 
Death rate of children, influence 

of the milk supply on, 54 
Deception in foods, 21 
Desiccated fruits, 147 
Desiccated vegetables, 156 
Dextrine, 3, 92, 103 
Dextrose, 3, 103 

production of, 93, 96 
Diastase, action of, on starch, 100 
Diet, balanced, 23 

function of sugar in, 101 
importance of carbohydrates in, 

88 
importance of fats in, 60 
importance of meat in, 78 
importance of spices in, 172 
Digestibility, coefficient of, 26 
Digestion, experiments with chem- 
ical preservatives, 136 
of protein, 16 
of starch, 88, 100 
stimulated by attractive foods, 
172 
Diphtheria and other diseases 

transmitted by milk, 46 
Drugs, chemical preservatives 

classed as, 135 
Drying, preservation by, 129 

sanitary conditions during, 130 
Dye, amount used in food, 126 
experiments with a poisonous, 
125 



INDEX 



203 



Dyes, aniline, 122 
harmless vegetable, 126 
methods of proving harmless, 124 
permitted by United States De- 
partment of Agriculture, 126 
testing for, 154 

Egg substitute, 122, 164 
Eggs, 163 

dried, 118 

preservation of, 138 

preserved, 118 

use of, in candy, 118 
Energy, method of measuring, 7 

obtained from food, 6 
Enzymes, 100 
Ether, 190 
Ethyl acetate, 144 
Evaporated milk, 39 
Excessive consumption of protein, 

26 
Exhausted spices, 178 
Experiments w^ith a poisonous dye, 

125 
Extract, almond, 186 

lemon, 184, 186 

orange, 186 
Extracts, artificial, 184 

flavoring, 180 

Eat, percentage of, in New York 
City milk, 37 

Fats, and oils, 4, 60 
acids in, 4, 63 
calorific value of, 10 
chemical composition of, 61 
decomposition of, 62 
digestion of, 4 
glycerin and acids in, 62 
in the diet, importance of, 60 
percentage of, in foods, 60 



Fats, and oils, rancidity of, 4 
Fatty acids, 63 

test for, 15 
Fehling's solution, 190 

use of, in testing for sugar, 15 
Ferric chloride, 190 
Ferrous sulphate, 191 
Filter paper, 195 
Filters, charcoal, 93, 94 
Flasks, 195 
Flavor, of fruits, 144 

of oils, 64 
Flavoring extracts, 180 

utility of, 180 
Flavoring matter for candy, 121 
Flour, barley, 162 

bleached, 161 

buckwheat, 162 

grades of, 160 

Graham, 160 

Indian corn, 162 

mixed, 161 

patent, 160 

rye, 162 

whole-wheat, 160 
Foam test for butter, 76 
Food, adulterated, 22 

amount consumed, 6 

amount of dyes used in, 126 

an ideal, 34 

as a source of energy, 6 

bread an ideal, 159 

cost of, 23 

definition of, 6, 7 

function of, in the human sys- 
tem, 6 

functions of, 7 

importance of milk as, 33 

method of measuring the energy 
of, 7 

necessity of chewing, 100 



204 



PUEE FOODS 



Food, oxidation of, in the human 
system, 6 

pure, definition of, 18 

staple, 36 
Food colors, 122 

aniline, 123 

harmless, 122 

vegetable, 123 
Food oils, 68 
Food value, of candy, 101 

of chocolate creams, 106 

of fruits, 146 

of jams and jellies, 149 

reduction of, 21 
Foods, adulterated, 18 

classes of, 2 

comparative cost of, 29 

composition of, 1, 11 

condimental, 172 

deception in, 21 

decomposed, preservation of, 138 

fraudulent coloring of, 122 

importance of analysis of, 4 

interchangeable, 24 

legal standards of, 22 

long-used, pure, 19 

misleading labels of, 21 

not sterilized by preservatives,139 

percentage of fats in, 60 

poisonous constituents of, 20 

preservation of, 127 

substitution of, 19 
Foose mills, 90 
Formaldehyde, 138 

test for, in milk, 41 
Fruit flavors, 187 
Fruit juices, testing for, 153 

testing for acidity of, 152 
Fruits, 141 

acids found in, 143 

canned, 148 



Fruits, cold storage of, 147 

composition of, 141, 145 

desiccated, 147 

dried, 147 

flavor of, 144 

food values of, 146 

fresh, good summer diet, 146 

mineral matter in, 144 

preserved, good winter diet, 146 

ripening of, 141 

testing for pectin, 152 

testing for starch, 152 
Fuchsin, 125 
Fuller's earth, 66 
Funnels, 195 

Gelatin, 118 

manufacture of, 84 

nutrient, preparation of, 55 
Germ separators, 90 
Germs of corn, separation of, 90 
Ginger, 175 

black, 175 

white, 175 
Glucose, 96 

composition of, 96, 103 

detection of, 121 

food value of, 101 

nutritive value of, 97 

production of, from starch, 92 
Gluten, 159 

composition of, 90 
Glycerin and acids in fats, 62 
Graduates, 195 
Graham flour, 160 
Grinding nutmegs, 178 
Gypsum, 163 

Harmless dye, experiments with, 

125 
Hazelnut oil, 68 



INDEX 



205 



Hesse, Dr. Bernhard C, 126 
Holt, Dr. Emmett, 54 
Honey, 96 

Human beings, action of preserv- 
atives on, 136 
Hydrochloric acid, 191 
Hydrogen peroxide, 139 

Indian corn flour, 162 
Inspected meat, 80 
Interchangeable foods, 24 
Iodine, 191 

Iodine test for starch, 15 
Iron oxide, 116 

Jams, 141, 148 

adulterated, 151 

composition of, 148 

food value of, 149 

testing for dyes, 154 
Jellies, 141, 148 

artificial, 150 

composition of, 149 

food value of, 149 

testing for dyes, 154 

wholesomeness of artificial, 151 
Jelly making, 149 

Lard substitutes, 66 
Lead acetate, 191 
Leavening agents, 165 
Lees, 143 

Legal standards of foods, 22 
Lemon extract, 184 

adulteration of, 186 
Levulose, 3, 96, 104 
Liebig's method of raising bread, 1 66 
Limewater, 192 
Linters, 65 
Litmus paper, 192 
Long-used foods, pure, 19 



Mace, 176 
Magnesium, 192 
Malt, 100 
Maltine, 100 
Maltose, 4, 96 

production of, from starch, 93 
Meat, characteristics of sound, 81 

cold storage of, 82 

danger of excessive use of, 79 

diseased, characteristics of, 81 

importance of, in the diet, 78 

inspected, 80 

preservation of, 138 

refrigeration of, 81 

similarity of various kinds of, 81 

substitutes for, 78 

testing for borax in, 85 

testing for sulphites in, 85 

unsanitary, 80 
Meats, 78 

chemical preservatives for, 83 
Methyl alcohol, 192 
Methyl orange, 192 
Microscopic examination of spices, 

179 
Milk, 33 

a staple food, 36 

action of bacteria on, 45 

amount consumed in New York 
City, 33 

bacteria in, 43, 45 

bacteria transmitted by, 46 

Buddeized, 52 

certified, 48 

comparative cost of, 38 

composition of, 35 

constituents of, 34, 40 

cream and butter, comparative 
cost of, 38 

daily ration of, 36 

determination of bacteria in, 54 



206 



PURE FOODS 



Milk, diphtheria and other diseases 
transmitted by, 46 

evaporated, 39 

high protein content of, 35 

importance of, as food, 33 

modified, 35 

nvitritive vahie of, 36 

Pasteurized, 50 

preservatives in, 49 

pure, production of, 47 

scarlet fever transmitted by, 46 

skim, 39 

sold in New York City, bacteria 
in, 53 

sterilized, 49 

supply, influence of, on death 
rate of children, 54 

test for borax in, 40 

test for formaldehyde in, 41 

typhoid fever transmitted by, 46 

variations in composition of, 37 

variations in bacteria content of, 
53 
Milk sugar, 40 
Milk test for butter, 76 
Mineral matter, and solids of milk, 
test for, 16 

definition of, 2 

digestion of, 5 

in foods, 5 

in fruits, 144 

test for, 16 
Mineral water, definition of, 6 
Misleading labels of foods, 21 
Mixed flour, 161 
Model milking room, 49 
Model stalls, 47 
Modern people well fed, 127 
Modified milk, 35 
Molasses, manufacture of, 98 
Mustard, 175 



Mustard, composition of, 175 
powdering of, 176 

New York City, amount of milk 
necessary for, 33 

bacteria in milk sold in, 53 
New York City milk, variations in 

composition of, 37 
Nitric acid, 192 
Nitric oxide, 161 
Nitrogen, importance of, in foods, 5 

organic, test for, 16 
Nutmeg, 176 
Nutmegs, composition of, 176 

grinding, 178 
Nutrient agar-agar, preparation of, 

59 
Nutrient gelatin, preparation of, 55 

sterilization of, 57 
Nutritive value of glucose, 97 
Nuts and candy, adult ration of, 102 

food value of, 101 

Oil, coconut, 64 

corn, 91 

cottonseed, 64 

hazelnut, 68 

olive, 66 

peanut, 68 

rapeseed, 68 

refining of, 66 

salad, 66 

sesame, 68 

sunflower seed, 68 

test for cottonseed, 70 
Oil cake, 91 
Oil press, 65 
Oils, 60 

determination of acidity of, 68 

flavor of, 64 

nutritive value of, 64 



INDEX 



207 



Oils, used for food, 68 
Oleic acid, 62 
Oleomargarine, 74 

manufacture of, 76 

wliolesomeness of, 75 
Olive oil, 66 

adulteration of, 67 

various grades of, 67 
Orange extract, 186 
Organic matter, definition of, 2 
Organic nitrogen, test for, 16 

Paints, made from casein, 40 
Palmitic acid, 62 
Paprika, 174 

Park, Dr. AVilliam H., 54 
Pasteurization, 131 

advantage of, 52 
Pasteurized milk, 50 
Patent flour, 160 
Peanut oil, 68 
Peanuts, composition of, 114 

food value of, 102 
Pectin, 145, 149 

testing fruits for, 152 
Pectose, 145 
Pepper, 177 

cayenne, 174 
Pepsin, digestion experiment with, 

16 
Petri dishes, 55, 196 
Phenolphthalein, 192 

use of, in testing for acids, 15 
Phosphate baking powder, 167 
Phosphate powders, wliolesomeness 

of, 168 
Phosphates, testing baking powders 

for, 170 
Phosphoric acid, 192 
Phosphorus necessary in the diet, 
169 



Pipestem triangles, 195 
Pipettes, 197 

Plate cultures of bacteria, 58 
Platinum, 197 
Platinum wire, 195 
Poisonous aniline dyes, 123 
Poisonous constituents of foods, 20 
Poisonous dye, experiments with, 

125 
Poisonous vegetable colors, 123 
Poisons, commonly consumed, 135 

cumulative, 134 

dose of, 134 
Pomace, 143 
Porcelain dish, 195 
Porcelain mortar, 195 
Potassium nitrate, 83 
Preservation, advantages of, 127 

by alcohol, 132 

by common salt, 132 

by drying, 129 

by hydrogen peroxide, 139 

by smoking, 132 

by spices, 133 

by sugar, 133 

by vinegar, 132 

methods of, in use, 128 

of decomposed foods, 138 . 

of foods, 127 

proper use of methods of, 128 
Preservatives, action of, on bac- 
teria, 137 

chemical, efficiency of, 133 

do not sterilize foods, 139 

experiments with, on human be- 
ings, 136 

in milk, 49 

objections to use of, in meats, 84 

vs. cleanliness, 138 
Process butter, 73 
Protein, calorific value of, 10 



208 



PURE FOODS 



Protein, digestion of, 16 

excessive consumption of, 26 

in cereals, 159 

present in milk, 35 
Protein content of milk, 35 
Proteins, 4 

digestion of, 5 
Pure food, definition of, 18 
Pure milk, production of, 47 
Pyroligneous acid, 132 

Kancid oils, test for, 15 
Rapeseed oil, 68 
Ration, daily, 23 

of a single food, cost of, 29 

of candy and nuts, 102 

of milk, 36 

standard, 24 

standard, definition of, 23 
Rations for children, 25 

special, 25, 26 

standard, 23 
Reagents, 189 

Reducing sugar, test for, 15 
Reduction of food value, 21 
Referee Board of United States 
Department of Agriculture, 
1>36 
Refiners' sirup, 97 
Refining of cane sugar, 98 
Refining oil, 66 
Refrigeration, 130 

length of, 131 

of meat, 81 
Renovated or process butter, 73 
Resorcin, 171, 192 
Rochelle salt, 169, 193 
Rye flour, 162 

Saffron substitute, 125 
St.-John's-bread, 116 



Salad oil, 66 

Saliva, digestion of starch by, 100 

Saltpeter, 83 

Sanitary conditions during drying, 

130 
Saponification, 63 
Savages, habits of eating, 1 
Scarlet fever transmitted by milk, 

46 
Sesame oil, 68 
Shakers, 91 
Shellac varnish, used on chocolate, 

116 
Sifting machines for cocoa, 113 
Silver nitrate, 193 
Sirup, concentration of, 96 

production of, from starch, 92 

purification of, 94 

refiners', 97 

table, 97 

vacuum pan for concentration of, 
95 
Sirups, 88 
Skim milk, 39 

Smoking, preservation by, 132 
Soap making, 69 
Sodium, metallic, 193 
Sodium acid sulphite, 193 
Sodium carbonate, 193 
Solids and mineral matter of milk, 

test for, 16 
Special rations, 25, 26 
Spices, 133, 172 

adulteration of, 177 

exhausted, 178 

importance of, in the diet, 172 

microscopic examination of, 179 
Standard ration, 24 

definition of, 23 
Standard rations and the cost of 
food, 23 



INDEX 



209 



Staple food, 36 
Starch, 88 

action of diastase on, 100 

calorific value of, 10 

conversion of, into sugar, 99 

conversion of, into sirup and 
sugar, 92 

digestion of, 100 

iodate paper, 193 

manufacture of, 91 

natural products containing, 89 

necessity of cooking, 88 

test for, 15, 99 

testing fruits for, 152 

transformation of, 3 
Steam sterilizer, 50 
Stearic acid, 62 

preparation of, 69 
Stearin, 61, 66 

preparation of, 68 
Sterilization, 131 

of apparatus, 55 

of culture medium, 57 
Sterilized milk, 49 
Substitutes for lard, 66 
Substitution of foods, 19 
Sucrose, 96, 103 
Sugar, 88 

cane, manufacture of, 98 

cane, refining of, 98 

function of, in the diet, 101 

milk, 40 

production of, from starch, 92, 99 

reducing test foi-, 15 

test for, by means of Fehling's 
solution, 15 

use of, as a preservative, 133 
Sugars, 3 

present in candy, 103 
Sulphites, 138 

testing for, in meats, 85 



Sulphur, 193 

Sulphur dioxide, testing for, 157 
Sulphuric acid, 194 
Sulj^hurous acid, 83 

injurious, 104 

testing for, in meats, 86 

use of, in candy, 104 

use of, in drying fruits, 129 
Sunnner diet, fresh fruits excellent 

for, 146 
Sunflower-seed oil, 68 

Table sirup, 97 
Tartaric acid, 143 

testing baking powders for, 170 
Tartrate powders, wholesomeness 

of, 168 
Test, for fatty acids, 15 

for mineral matter, 16 

for organic nitrogen, 16 

for reducing sugar, 15 

for solids and mineral matter of 
milk, 16 

for starch, 15 
Test tube, 195 
Theobromine, 112 
Thermometers, 196 
Tonka bean, 183 
Tonka extract, 183 
Tripod, 196 
Tuberculosis transmitted by milk, 

46 
Turmeric paper, 194 

use of, in testing for borax, 41 
Typhoid fever transmitted by milk, 
46 

Unsanitary meat, 80 

Vacuum pan, 95 
Valerianic acid, 145 



210 



PUEE FOODS 



Vanilla bean, 180 

varieties of, 182 
Vanilla extract, preparation of, 
182 

pure, 183 
Vanilla extracts, composition of, 

185 
Vanilla vine, 181 
Vanillin, 182 
Variations in composition of milk, 

37 
Vegetable colors, poisonous, 123 
\'egetable dyes, 126 
^'egetable food colors, 123 
Vegetables, 155 

adulteration of, 155 

composition of, 155, 15G 

copper in, 156 

desiccated, 156 

testing for starch in, 99 
Vegetables, water in, 155 



Vinegar, use of, as a preservative, 
132 

Washington Monument, 98 
Water, in bread, 163 
in vegetables, 155 
Water bath, 196 
Week's food for four adults, 28 
Wheat flour, composition of, 160 
AVhole-wheat flour, 160 
Wholesomeness of oleomargarine, 

75 
Wild mace, 176 
Winter diet, preserved fruits good 

for, 146 
Wire gauze, 196 
Witte's peptone, 194 
AVood alcohol, 194 

Yeast, discovery of, 165 
Yeast plant, 165 



ANNOUNCEMENTS 



EXPERIMENTAL DAIRY 
BACTERIOLOGY 

By H. L. RUSSELL, Dean of the College of Agriculture, University of Wisconsin, 

and E. G. HASTINGS, Assistant Professor of Agricultural 

Bacteriology, University of Wisconsin 



New l2mo. Cloth. 147 pages. Illustrated. List price, $1.00 j mailing price, ^1.05 



THE purpose of the course here outlined is to train the 
student in those bacteriological processes that are 
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to dairy processes. This work is of fundamental importance 
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changes going on in milk and its products, whether he is con- 
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The attempt has been made to keep the scope of this work 
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FUNGOUS DISEASES OF PLANTS 

By Benjamin Minge Duggar 
Professor of Plant Physiology in Cornell University 



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IN this book are presented many of the vital facts brought 
to light by modern research in plant pathology, which 
should be invaluable to farmers, gardeners, and every one 
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There is embodied a comprehensive discussion of the chief 
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AN ELEMENTARY STUDY OF 
CHEMISTRY 

By WILLIAM McPHERSON, Professor of Chemistry in Ohio State University, 
and WILLIAM E. HENDERSON, Associate Professor of Chemistry in 
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i2mo. Cloth. 434 pages. Illustrated. List price, ;^i. 25 5 mailing price, ^1.40 



THIS book is the outgrowth of many years of experience in 
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readily understood to those which are more difficult to grasp. 
The language is simple and as free as possible from unusual and 
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defined. The outline is made very plain, and the paragraphing 
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The book is in no way radical, either in the subject-matter 
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EXERCISES IN CHEMISTRY. By William McPherson and 
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